42 research outputs found
Softversko reÅ”enje za dizajniranje karakteristika analognih vizuelnih pokazivaÄa bazirano na primeni ekspertnih sistema
Verifikovano tehniÄko reÅ”enj
Conductometric study of sodium dodecyl sulfate - nonionic surfactant (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85) mixed micelles in aqueous solution
The present study is concerned with the determination of the critical micelle concentration (cmc) of mixed micelles of sodium dodecyl sulfate with one of five nonionic surfactants (Triton X-100, Tween 20, Tween 60, Tween 80 or Tween 85) from conductance measurements. Based on the calculated values of the Ī² parameters we have noticed that SDS-nonionic surfactants mostly showed strong synergistic effect. It was found that nonionic surfactants with mainly longer and more hydrophobic tail show stronger interactions with hydrophobic part of SDS, thus expressing stronger synergism. In SDS-Tween 80 binary system the strongest synergistic effect was noticed. SDS-Tween 85 micellar system showed antagonistic effect, most probably because the presence of the double bond in its three hydrophobic tails (three C18 tails) makes it sterically rigid
Boundary effects in the stepwise structure of the Lyapunov spectra for quasi-one-dimensional systems
Boundary effects in the stepwise structure of the Lyapunov spectra and the
corresponding wavelike structure of the Lyapunov vectors are discussed
numerically in quasi-one-dimensional systems consisting of many hard-disks.
Four kinds of boundary conditions constructed by combinations of periodic
boundary conditions and hard-wall boundary conditions are considered, and lead
to different stepwise structures of the Lyapunov spectra in each case. We show
that a spatial wavelike structure with a time-oscillation appears in the
spatial part of the Lyapunov vectors divided by momenta in some steps of the
Lyapunov spectra, while a rather stationary wavelike structure appears in the
purely spatial part of the Lyapunov vectors corresponding to the other steps.
Using these two kinds of wavelike structure we categorize the sequence and the
kinds of steps of the Lyapunov spectra in the four different boundary condition
cases.Comment: 33 pages, 25 figures including 10 color figures. Manuscript including
the figures of better quality is available from
http://newt.phys.unsw.edu.au/~gary/step.pd
Razvoj softverske aplikacije univerzalne jednaÄine za proraÄun promene profita
Verifikovano tehniÄko reÅ”enj
Hopping dynamics for localized Lyapunov vectors in many-hard-disk systems
The dynamics of the localized region of the Lyapunov vector for the largest
Lyapunov exponent is discussed in quasi-one-dimensional hard-disk systems at
low density. We introduce a hopping rate to quantitatively describe the
movement of the localized region of this Lyapunov vector, and show that it is a
decreasing function of hopping distance, implying spatial correlation of the
localized regions. This behavior is explained quantitatively by a brick
accumulation model derived from hard-disk dynamics in the low density limit, in
which hopping of the localized Lyapunov vector is represented as the movement
of the highest brick position. We also give an analytical expression for the
hopping rate, which is obtained us a sum of probability distributions for brick
height configurations between two separated highest brick sites. The results of
these simple models are in good agreement with the simulation results for
hard-disk systems.Comment: 28 pages, 13 figure
Theoretical and experimental analysis of dynamic processes of pipe branch for supply water to the Pelton turbine
The paper presents the results of the analysis of pipe branch A6 to feed the Hydropower Plant āPeruÄicaā with integrated action Pelton turbines. The analysis was conducted experimentally (tensometric) and numerically. The basis of the experimental research is the numerical finite element analysis of pipe branch A6 in pipeline C3. Pipe branch research was conducted in order to set the experiment and to determine extreme stress states. The analysis was used to perform the determination of the stress state of a geometrically complex assembly. This was done in detail as it had never been done before, even in the design phase. The actual states of the body pipe branch were established, along with the possible occurrence of water hammer accompanied by the appearance of hydraulic oscillation. This provides better energetic efficiency of the turbine devices. [Projekat Ministarstva nauke Republike Srbije, br. TR35049 and br. TR 33040
Time-dependent mode structure for Lyapunov vectors as a collective movement in quasi-one-dimensional systems
Time dependent mode structure for the Lyapunov vectors associated with the
stepwise structure of the Lyapunov spectra and its relation to the momentum
auto-correlation function are discussed in quasi-one-dimensional many-hard-disk
systems. We demonstrate mode structures (Lyapunov modes) for all components of
the Lyapunov vectors, which include the longitudinal and transverse components
of their spatial and momentum parts, and their phase relations are specified.
These mode structures are suggested from the form of the Lyapunov vectors
corresponding to the zero-Lyapunov exponents. Spatial node structures of these
modes are explained by the reflection properties of the hard-walls used in the
models. Our main interest is the time-oscillating behavior of Lyapunov modes.
It is shown that the largest time-oscillating period of the Lyapunov modes is
twice as long as the time-oscillating period of the longitudinal momentum
auto-correlation function. This relation is satisfied irrespective of the
particle number and boundary conditions. A simple explanation for this relation
is given based on the form of the Lyapunov vector.Comment: 39 pages, 21 figures, Manuscript including the figures of better
quality is available from http://www.phys.unsw.edu.au/~gary/Research.htm
Uticaj meteoroloŔkih parametara na koncentraciju SO2 u Obrenovcu, Srbija
In this paper, the impacts of some meteorological parameters on the SO2 concentrations in the City of Obrenovac are presented. The City of Obrenovac is located in the north-west part of Serbia on the banks of the River Sava. The observed source emission, the power plants TENT A and B are situated on the bank of the Sava River in the vicinity of Obrenovac. During the period from January to November 2006, the concentrations of sulfur dioxide in the air at 4 monitoring sites in Obrenovac were measured. It was noticed that the maximal measured daily concentrations of sulfur dioxide ranged from 1 Ī¼g m-3 (16th November, 2006) to 98 Ī¼g m-3 (29th January 2006) and lie under the maximal allowed concentration value according to the Serbian Law on Environmental Protection. The measured sulfur dioxide concentrations mostly showed characteristics usual for a daily acidification sulfur dioxide cycle, excluding the specificities influenced by the measuring site itself. Sulfur dioxide transport was recorded at increased wind speeds, primarily from the southeast direction. Based on the impact of meteorological parameters on the sulfur dioxide concentration, a validation of the monitoring sites was also performed from the aspect of their representivity.U radu su predstavljeni rezultati monitoringa koncentracije SO2 u vazduhu u Obrenovcu koji se nalazi na severozapadu Srbije na obalama reke Save. Posmatran je uticaj meteoroloÅ”kih parametara na koncentraciju SO2 emitovanog iz termoelektrana TENT A i B koji se smatraju najveÄim izvorima emisije. U periodu od januara do novembra 2006. godine praÄene su koncentracije sumpor-dioksida u vazduhu na 4 merna mesta lokalizovana na razliÄitim udaljenostima od izvora emisije. Maksimalne izmerene dnevne koncentracije sumpor-dioksida su se kretale od 1 Ī¼g m-3 (16. novembra, 2006) do 24 Ī¼g m-3 (29. januara, 2006). Izmerene promene koncentracija sumpor-dioksida uglavnom pokazuju uobiÄajene karakteristike dnevne acidifikacije ciklusa uz razlike koje potiÄu od osobenosti mernih mesta. Transport sumpor-dioksida zabeležen je pri pojaÄanom vetru prvenstveno iz jugoistoÄnog pravca. Na osnovu korelacionih odnosa izmeÄu koncentracije sumpor-dioksida i odgovarajuÄih meteroloÅ”kih parametara izvrÅ”ena je karakterizacija mernih mesta u pogledu njihove reprezentativnosti za merenje sumpor-dioksida
Uticaj meteoroloŔkih parametara na koncentraciju SO2 u Obrenovcu, Srbija
In this paper, the impacts of some meteorological parameters on the SO2 concentrations in the City of Obrenovac are presented. The City of Obrenovac is located in the north-west part of Serbia on the banks of the River Sava. The observed source emission, the power plants TENT A and B are situated on the bank of the Sava River in the vicinity of Obrenovac. During the period from January to November 2006, the concentrations of sulfur dioxide in the air at 4 monitoring sites in Obrenovac were measured. It was noticed that the maximal measured daily concentrations of sulfur dioxide ranged from 1 Ī¼g m-3 (16th November, 2006) to 98 Ī¼g m-3 (29th January 2006) and lie under the maximal allowed concentration value according to the Serbian Law on Environmental Protection. The measured sulfur dioxide concentrations mostly showed characteristics usual for a daily acidification sulfur dioxide cycle, excluding the specificities influenced by the measuring site itself. Sulfur dioxide transport was recorded at increased wind speeds, primarily from the southeast direction. Based on the impact of meteorological parameters on the sulfur dioxide concentration, a validation of the monitoring sites was also performed from the aspect of their representivity.U radu su predstavljeni rezultati monitoringa koncentracije SO2 u vazduhu u Obrenovcu koji se nalazi na severozapadu Srbije na obalama reke Save. Posmatran je uticaj meteoroloÅ”kih parametara na koncentraciju SO2 emitovanog iz termoelektrana TENT A i B koji se smatraju najveÄim izvorima emisije. U periodu od januara do novembra 2006. godine praÄene su koncentracije sumpor-dioksida u vazduhu na 4 merna mesta lokalizovana na razliÄitim udaljenostima od izvora emisije. Maksimalne izmerene dnevne koncentracije sumpor-dioksida su se kretale od 1 Ī¼g m-3 (16. novembra, 2006) do 24 Ī¼g m-3 (29. januara, 2006). Izmerene promene koncentracija sumpor-dioksida uglavnom pokazuju uobiÄajene karakteristike dnevne acidifikacije ciklusa uz razlike koje potiÄu od osobenosti mernih mesta. Transport sumpor-dioksida zabeležen je pri pojaÄanom vetru prvenstveno iz jugoistoÄnog pravca. Na osnovu korelacionih odnosa izmeÄu koncentracije sumpor-dioksida i odgovarajuÄih meteroloÅ”kih parametara izvrÅ”ena je karakterizacija mernih mesta u pogledu njihove reprezentativnosti za merenje sumpor-dioksida
Utilization of geothermal springs as a renewable energy source: Vranjska Banja case study
Despite the significant natural potential, geothermal energy in Serbia has traditionally been used in balneology and recreation, while its share in the countryās total energy balance is almost negligible (0.05%). The present paper deals with the City Municipality of Vranjska Banja as a pioneer in the territory of Serbia in using geothermal energy for heating. The concept and methodology of the present research are directly related to the utilization of geothermal resources for district heating in the Vranjska Banja area. The presented analysis includes: determining the available amount of energy, identifying the energy needs of selected public
facilities, and the estimation of investment necessary for energy utilization. A survey, combined with field research, is focused on four public facilities connected to the heating system relying on geothermal sources, as well as on two facilities that should be connected to the system in the next phases. The results show economic, ecological, and technological advantages of using geothermal heating systems, as well as the acceptable price of equipment maintenance. An economic assessment of the transition of one facility from the existing heating system to a system relying on geothermal energy has also been made. The analysis confirms the cost-effectiveness
of using geothermal energy and reveals numerous ecological advantages (safe heating, absence of CO2 emission) over other energy sources