Serbian Institute for Multidisciplinary Research

Belgrade, Serbia

Serbian Institute for Multidisciplinary Research

Belgrade, Serbia
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Popovic D.B.,University of Belgrade | Popovic D.B.,University of Aalborg | Popovic M.B.,University of Belgrade | Popovic M.B.,University of Aalborg | Popovic M.B.,Serbian Institute for Multidisciplinary Research
Progress in Brain Research | Year: 2011

This chapter sheds light on several issues that are being explored to optimize the application of electrical stimulation in a motor neural prosthesis (MNP) for the restoration of movement in humans with paralysis. Although several MNPs are commercially available, there are issues that limit their use in therapy and/or daily assistance: (1) the users' intention of what and how to move needs to be effectively transmitted to the MNP controller; (2) interface to the neural pathways that leads to physiological-like activation should be improved; (3) artificial control of the MNP should match the biological control of the preserved biological systems; and (4) sensors information should be fused and provided to both the controller of the MNP and the user. We suggest that with the improved use of cortical or other physiological signals, application of multipad electrodes with special protocols, rule-based control that mimics biological control, and with the incorporation of micro- and nanotechnologies, wireless communications, and microcontrollers, the MNP operation can be greatly enhanced. The chapter specifically addresses the control of MNP for the upper extremities and provides details on the new surface multipad electrodes that are of interest for neurorehabilitation of stroke patients. © 2011 Elsevier B.V.


Scepanovic M.,Institute of Physics | Grujic-Brojcin M.,Institute of Physics | Vojisavljevic K.,Serbian Institute for Multidisciplinary Research | Bernikc S.,Jozef Stefan Institute | Sreckovic T.,Serbian Institute for Multidisciplinary Research
Journal of Raman Spectroscopy | Year: 2010

Raman scattering spectroscopy has been used for the characterization of zinc oxide nanoparticles obtained by mechanical activation in a high-energy vibro-mill and planetary ball mill. Raman modes observed in spectra of nonactivated sample are assigned to Raman spectra of the ZnO monocrystal, while the spectra of mechanically activated samples point out to the structural and stoichiometric changes, depending on the milling time and the choice of equipment. Observed redshift and peak broadening of the E2 high and E1 (LO) first-order Raman modes are attributed to increased disorder induced by mechanical milling, followed by the effects of phonon confinement due to correlation length decrease. The additional modes identified in Raman spectra of activated ZnO samples are related to the surface optical phonon modes, due to the intrinsic surface defects and presence of ZrO2as extrinsic defects introduced by milling in zirconia vials. © 2009 John Wiley & Sons, Ltd.


Jovalekic C.,Serbian Institute for Multidisciplinary Research | Zdujic M.,Serbian Academy of Science and Arts
Ceramics International | Year: 2010

The effect of thermal treatment atmosphere (argon, air or oxygen) on the electret behavior of bismuth titanate (Bi4Ti3O12) ceramics was investigated. Polycrystalline ferroelectric ceramics were prepared by reactive liquid phase sintering. Sintered samples were polarized applying an electric field, Ep = 1 MV m-1 at 100 °C for 60 min. Effective surface density, σeff of free charges was determined by compensation voltage measurements. Thermally treated samples in oxygen atmosphere exhibit a significant decrease of σeff while those treated in argon exhibit an increase of σeff accompanied by the improvement in stability of electret charge. In all cases homocharge with a time independent sign was obtained. © 2009 Elsevier Ltd and Techna Group S.r.l.


Nikolic N.D.,University of Belgrade | Brankovic G.,Serbian Institute for Multidisciplinary Research
Materials Letters | Year: 2012

Formation of open porous copper structures by the electrodeposition processes in the hydrogen co-deposition range was considered. Morphologies of copper deposits obtained by the reversing current (RC) regimes at the same average current density but with the different the anodic current density/anodic pulse ratios were compared with those obtained by the pulsating current (PC) regime at the same average current density and in the constant galvanostatic mode at the current density which was equal to this average current density. The considerable increase of the specific surface area of the honeycomb-like structures, determined by the increase of number of holes, as well as by the decrease of both holes size and wall width among them, can be attained if the appropriate parameters of the RC regimes are applied. In this way, it is shown that the regime of reversing current (RC) is superior in the production of open porous structures suitable to be used as electrodes in many electrochemical devices in relation to other current regimes of electrolysis, such as the PC and the galvanostatic regimes. © 2011 Elsevier B.V. All rights reserved.


Nikolic N.D.,University of Belgrade | Brankovic G.,Serbian Institute for Multidisciplinary Research | Popov K.I.,University of Belgrade
Materials Chemistry and Physics | Year: 2011

Optimization of process of formation of open and porous copper electrodes, denoted as the honeycomb-like ones, by the regime of pulsating current (PC) is considered. The square-waves PC were consisted of the same amplitude current density and pause duration of 10 ms, while the analyzed deposition pulses were: 1, 4, 7, 10 and 20 ms. Morphologies of electrodeposited copper and the quantities of evolved hydrogen during electrodeposition processes were compared with the surface morphology and the quantity of evolved hydrogen obtained by copper electrodeposition in the galvanostatic mode. In galvanostatic mode, electrodeposition of copper was performed at a current density which corresponded to the amplitude current density in the PC regimes. Honeycomb-like deposits were formed at the constant current density and by the PC regimes with deposition pulses of 7, 10 and 20 ms. The mixture of holes constructing the honeycomb-like structure and dish-like holes was obtained with a deposition pulse of 4 ms. Finally, dish-like holes were only formed with a deposition pulse of 1 ms. The change of the shape of holes was discussed by the change of hydrodynamic conditions in the near-electrode layer caused by evolved hydrogen. The specific energy consumption in the PC regimes of electrolysis was also discussed. Analysis of the specific energy consumption showed that energy saving of about 15% can be attained in the production of honeycomb-like electrodes by the choice of the appropriate PC regime. © 2010 Elsevier B.V. All rights reserved.


Nikolic N.D.,University of Belgrade | Brankovic G.,Serbian Institute for Multidisciplinary Research
Electrochemistry Communications | Year: 2010

Copper electrodeposition processes in the hydrogen co-deposition range by the pulsating current (PC) regime were examined by the determination of the average current efficiency of hydrogen evolution and by the scanning electron microscopic (SEM) analysis of the morphology of the formed deposits. The two sets of the square-wave PC of the same pause to pulse ratios, but with different duration of deposition pulses and pauses were analyzed. The one set of square-wave PC was with the constant pause duration and different deposition pulses. In the other set, the deposition pulse was constant while the pause duration was varied. The obtained results were compared with those obtained by electrodeposition at the constant overpotential from solutions of different CuSO4 and H2SO4 concentrations. It was found that the effect of the increasing deposition pulse was equivalent to the decreasing CuSO4 concentration, while the effect of the decreasing pause duration was equivalent to the increasing H2SO4 concentration. It is shown that it is possible to achieve a substitution of more solutions of different CuSO4 and H2SO4 concentartions by the use of the only one solution if the appropriate PC parameters were applied, what can be of high technological significance. © 2010 Elsevier B.V. All rights reserved.


Jaric I.,Serbian Institute for Multidisciplinary Research | Ebenhard T.,Swedish University of Agricultural Sciences | Lenhardt M.,Sinisa Stankovic Institute for Biological Research
Reviews in Fish Biology and Fisheries | Year: 2010

Populations of six sturgeon species in the Danube River (beluga, Russian sturgeon, stellate sturgeon, sterlet, ship sturgeon and Atlantic sturgeon) have experienced severe decline during the last several decades, mostly due to the unsustainable fishery, river fragmentation and water pollution. Present lack of knowledge on basic sturgeon demography, life history and relative effects of different negative factors is further hindering implementation of efficient policy and management measures. In the present study, population viability analysis in a Vortex simulation model has been conducted in order to assess the state of the six Danube sturgeon species, their future risk of extinction and to determine the most suitable conservation and management measures. Population viability analysis has revealed a large sensitivity of the Danube sturgeon populations to changes in the natural mortality, fecundity, age at maturity and spawning frequency. It was also confirmed that the sturgeons are highly susceptible to even moderate levels of commercial fishery, and that their recovery is a multi-decadal affair. Stocking with adult individuals was shown to produce considerably greater effect on population persistence than stocking with juveniles, but the latter approach is probably still preferable since it avoids many inherent problems of aquaculture cultivation. This study represents the first population viability analysis of the Danube sturgeons. © 2009 Springer Science+Business Media B.V.


Jaric I.,Serbian Institute for Multidisciplinary Research | Jaric I.,Leibniz Institute of Freshwater Ecology and Inland Fisheries | Gessner J.,Leibniz Institute of Freshwater Ecology and Inland Fisheries
Scientometrics | Year: 2012

Sturgeon species are among the commercially most valuable and the most endangered groups of fish. To assess the existing literature published within the field of sturgeon research over the past 15 years (1996-2010) we applied a bibliometric approach, in order to identify patterns and trends of the published research in this field. The analysis was performed based upon articles obtained from the ISI Web of Knowledge online database. The results revealed that although all 27 sturgeon species have been objects of the research, species that are endangered or facing a high probability of extinction have received disproportionately less attention. White sturgeon (Acipenser transmontanus) was the most frequently studied species, but it was recently surpassed by Persian sturgeon (A. persicus). Early life phases have been among the central objects of the research, and genetics, especially the use of microsatellite DNA, is becoming increasingly popular and had the highest impact. Research related to aquaculture was prominent, while the research related to hybrids (as a commodity of aquaculture production) was decreasing in popularity. Papers dealing with conservation issues were most frequently focused on European sturgeon (A. sturio). A steady increase in the number of published articles over time was observed. However, the overall citation rate declined significantly over time. During the period reviewed, the sturgeon research published in peer reviewed journals dominantly originated from the USA and EU. Nevertheless, considering the current trend in output, it is very likely that the Asian countries, mainly Iran and China, will surpass them within the next 5-10 years. International and inter-institutional collaboration both tended to increase the impact of the research. Stimulation and improvement of the international cooperation should be considered as future priorities. © 2011 Akadémiai Kiadó, Budapest, Hungary.


Jaric I.,Serbian Institute for Multidisciplinary Research | Ebenhard T.,Swedish University of Agricultural Sciences
Wildlife Biology | Year: 2010

It is a very important, but also a very difficult task, to establish how long a certain species has to remain unregistered before we can declare it extinct. The wrong assumption regarding species extinction could result in a type I or type II statistical error, leading to inappropriate management actions or even species extinction. Recent development of the methods for inferring the threat of extinction, when the only available information is a record of sightings, has enabled a quantitative approach to the problem. In our study we present an index that infers extinction probability based on trends in sighting intervals. Our study comprises a description of the sighting trend index, a sensitivity analysis and an application of the index to the sighting record of the black-footed ferret Mustela nigripes. The main advantage of this method could be its sensitivity to changes in sighting frequency within the sighting record. However, further testing of the method on different data sets could be important for gaining additional knowledge regarding its adequate application in the field of conservation biology. © 2010 Wildlife Biology, NKV.


Komljenovic M.,Serbian Institute for Multidisciplinary Research | Bascarevic Z.,Serbian Institute for Multidisciplinary Research | Bradic V.,Serbian Institute for Multidisciplinary Research
Journal of Hazardous Materials | Year: 2010

This paper investigates the properties of geopolymer obtained by alkali-activation of fly ash (FA), i.e. the influence of characteristics of the representative group of FA (class F) from Serbia, as well as that of the nature and concentration of various activators on mechanical and microstructural properties of geopolymers. Aqueous solutions of Ca(OH)2, NaOH, NaOH+Na2CO3, KOH and sodium silicate (water glass) of various concentrations were used as alkali activators. It was established that the nature and concentration of the activator was the most dominant parameter in the alkali-activation process. In respect of physical characteristics of FA, the key parameter was fineness. The geopolymer based on FA with the highest content of fine particles (<43μm), showed the highest compressive strength in all cases. Regardless of FA characteristics, nature and concentration of the activator, the alkali-activation products were mainly amorphous. The formation of crystalline phases (zeolites) occurred in some cases, depending on the reaction conditions. The highest compressive strength was obtained using sodium silicate. Together with the increase of sodium silicate SiO2/Na2O mass ratio, the atomic Si/Al ratio in the reaction products was also increased. Under the experimental conditions of this investigation, high strength was directly related to the high Si/Al ratio. © 2010 Elsevier B.V.

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