17 results on '"Savić, Igor"'
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2. The He–H3+ complex. II. Infrared predissociation spectrum and energy term diagram
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Salomon, Thomas, primary, Brackertz, Stefan, additional, Asvany, Oskar, additional, Savić, Igor, additional, Gerlich, Dieter, additional, Harding, Michael E., additional, Lipparini, Filippo, additional, Gauss, Jürgen, additional, van der Avoird, Ad, additional, and Schlemmer, Stephan, additional
- Published
- 2022
- Full Text
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3. Formation of H 3 + in Collisions of H 2 + with H 2 Studied in a Guided Ion Beam Instrument
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Savić, Igor, primary, Schlemmer, Stephan, additional, and Gerlich, Dieter, additional
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- 2020
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4. Evaluation of the Final Time and Velocity of a 100 m Run Under the Realistic Conditions
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Janjić, Nataša, primary, Kapor, Darko, additional, Doder, Dragan, additional, and Savić, Igor, additional
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- 2019
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5. The Hβ line dip shift measurements in wide range of plasma electron density
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Savić, Igor, primary, Mijatović, Zoran, additional, Gajo, Teodora, additional, Gavanski, Lazar, additional, and Djurović, Stevica, additional
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- 2019
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6. Utjecaj zagrijavanja TIG postupkom na mehanička svojstva pri ravnanju limova aluminijeve legure 5083 H321
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Pentek, Ivan, Savić, Igor, Bičić, Milan, Špada, Vedrana, Bilić, Josipa, Špada, Ener, Bušić, Matija, Leder Horina, Jasna, and Tropša, Vlado
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TIG ,5083 H321 ,postupak ravnanja ,mehanička svojstva - Abstract
Pri izlaganju materijala u obliku limova uvjetima toplinske ili površinske obrade moguća jest neželjena promjena oblika ulaznog materijala. Važno je kod ispravljanja navedenog stanja obratiti pažnju na postupak koji se koristi, s ciljem očuvanja mehaničkih svojstava konstrukcije. U ovome radu se istražuje utjecaj zagrijavanja aluminijeve legure 5083 H321 TIG postupkom unosa topline na mehanička svojstva limova. Uz analizu kemijskog sastava pomoću optičkog emisijskog spektrometra, u svrhu usporedbe svojstava prije i nakon zagrijavanja, odrađeno je ispitivanje savijanjem u tri točke i vlačno ispitivanje na univerzalnoj statičkoj kidalici te metalografska analiza na optičkom metalografskom mikroskopu. Navedena ispitivanja su se provodila na uzorcima iz limova koji su bili podvrgnuti različitoj pripremi površine, različitim uvjetima unosa topline, broja prolaza alata te različitim uvjetima ohlađivanja nakon unosa topline. Promatrane su vrijednosti odnosno promjene u vlačnoj čvrstoći i istezljivosti (u %) te promjene u mikrostrukturi 5083 H321 legure u zoni utjecaja topline.
- Published
- 2022
7. ISPITIVANJE UTJECAJA PARAMETARA RAVNANJA LIMOVA TIG POSTUPKOM NA MEHANIČKA SVOJSTVA ALUMINIJEVIH LIMOVA
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Savić, Igor
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Al-5083 H321, ravnanje limova, AlMg4.5Mn0.7, TIG , TIG ravnanje - Abstract
U ovome radu opisano je ispitivanje utjecaja ravnanja limova TIG postupkom na mehanička svojstva aluminijevih limova legure 5083 H321. Svrha rada je bila optimizacija postupka ravnanja eksperimentalnim određivanjem i usporedbom mehaničkih svojstava referentnog materijala i materijala nakon različitih uvjeta grijanja TIG postupkom. Provedbom vlačnog testa i ispitivanja savijanjem potvrđeno je kako limovi koji su dva puta grijani, ohlađeni vodom, kao i oni koji na svojoj površini imaju aluminijev oksid, nemaju značajnija smanjenja mehaničkih svojstava. Prema rezultatima rada mogu se propisati postupci ravnanja i uvesti u proizvodnju uz zahtjev za odobrenje postupka od strane certifikacijskog tijela koje za atestaciju postupka, postupak mora potvrditi uvidom u eksperimentalne mjeriteljske podatke
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- 2022
8. Controlled synthesis and analysis of He–H+3in a 3.7 K ion trap
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Savić, Igor, primary, Gerlich, Dieter, additional, Asvany, Oskar, additional, Jusko, Pavol, additional, and Schlemmer, Stephan, additional
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- 2015
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9. Some Routes in Forming C[sub 3]H[sub n]+] Ions and Deuterated Variants under Interstellar Conditions
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Savić, Igor, primary and Gerlich, Dieter, additional
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- 2006
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10. Formation of H3+ in Collisions of H2+ with H2 Studied in a Guided Ion Beam Instrument.
- Author
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Savić, Igor, Schlemmer, Stephan, and Gerlich, Dieter
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- 2020
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11. Formation of Small Hydrocarbon Ions Under Inter- and Circumstellar Conditions: Experiments in Ion Traps
- Author
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Savić, Igor, Gerlich, Dieter, Seifert, Gotthard, Glosik, Juraj, and Technische Universität Chemnitz
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deuteration ,C3D+ ,ion-molecule reaction ,interstellar molecules ,C3HD ,C3+ ,ddc:520 ,laboratory astrochemistry ,hydrogenation ,radiative association ,ion-trap ,neutral carbon molecules - Abstract
Using ion-trapping techniques, selected laboratory experiments on ion-molecule reactions of astrophysical interest have been performed. For the first time a carbon beam source has been integrated into an ion trapping machine for studying collisions between ions and neutral carbon atoms and molecules. Results are presented for the interaction of D3+ ions stored in a ring-electrode trap (RET), with a beam of hot neutral carbon molecules, Cn (n = 1, 2, 3). The measured reaction rate coefficients are up to a factor two smaller than values presently used in astrophysical models. In order to complete our knowledge about the ion chemistry involving three carbon atoms, detailed investigations of reactions of C3+, C3H+ and C3H3+ with H2 and HD have been performed between 15 K and room temperature. These studies have been performed in a second apparatus, a variable-temperature 22-pole trap machine (VT-22PT). Results include reactive collisions, deuteration and radiative association. It is discussed in connection with the increase in lifetime of the C3+ + H2 collision complexes with falling temperature, what could be responsible for producing more C3H+ at 15 K. Tunneling is excluded. In C3+ + HD collisions an isotope effect has been detected, the C3D+ product ions being slightly more abundant than C3H+. Comparison of the reaction of C3H+ primary ions with HD and H2 gas revealed that the deuterated molecules are significantly more reactive. The process of radiative association of C3H+ and for the first time of C3+ with hydrogen molecules has been observed. An analysis of the data shows that radiative association becomes slower, if the neutral reactant is deuterated. Finally, the theoretical prediction from ab initio calculations that C3H3+ does not exchange an H for a D in collisions with HD, has been proven in an ion trap experiment. Careful analysis of all competing processes allows the conclusion that the rate coefficient is smaller than 4x10-16 cm3s-1 at 15 K. Unter Verwendung von zwei Speicherapparaturen wurden ausgewählte, astrophysikalische wichtige Ionen-Molekülreaktionen untersucht. Durch die Kombination einer Kohlenstoffquelle mit einem Ionenspeicher, in dem so Reaktionen zwischen Ionen und Kohlenstoffmolekülen oder -atomen untersucht werden können, wurde Neuland betreten. Es werden Ergebnisse vorgestellt für die Reaktion von D3+ Ionen, die in einem Ringelektrodenspeicher gefangen sind, mit einem Strahl von heißen Cn (n = 1, 2, 3). Die gemessenen Ratenkoeffizienten sind nur halb so groß wie die Werte, die in astrophysikalischen Modellen verwendet werden. Um die Kenntnis über alle möglichen Reaktionen, bei denen drei C-Atome beteiligt sind, abzurunden, wurden zwischen 15 K und Zimmertemperatur die Reaktionen zwischen C3+, C3H+ und C3H3+ Ionen mit H2 und HD in vielen Details untersucht. Diese Experimente wurden in einer zweiten Apparatur durchgeführt, in der ein temperaturvariabler 22-Polspeicher das zentrale Element ist (VT-22PT). Berichtet werden Ergebnisse zu reaktiven Stößen, zur Deuterierung von Kohlenwasserstoffen und zur Strahlungsassoziation. In der Diskussion bleibt offen, was - in Verbindung mit der von 300 K zu 15 K zunehmenden Lebensdauer - der Grund dafür sein kann, daß die Bildung des exothermen Produkts C3H+ anwächst. Der Tunneleffekt scheidet aus. Bei der Reaktion C3+ + HD wurde ein Isotopeneffekt beobachtet, das C3D+ Produkt wird etwas häufiger gebildet als C3H+. Ein Vergleich der Reaktion zwischen C3H+ Ionen mit HD bzw. H2 zeigt, daß das deuterierte Molekül wesentlich reaktiver ist. Es wurden Ratenkoeffizienten für die Strahlungsassoziation von H2 Molekülen mit C3H+ und erstmals mit C3+ Ionen gemessen. Die Auswertung der Daten zeigt, dass der Prozeß langsamer abläuft, wenn der neutrale Stoßpartner deuteriert ist. Schließlich wurde experimentell die theoretische Vorhersage überprüft, dass C3H3+ keinen H-D Austausch mit HD eingeht. Eine sorgfältige Analyse aller konkurrierenden Prozesse ergab, dass bei 15 K der Raten koeffizient kleiner als 4x10-16 cm3s-1 ist.
- Published
- 2004
12. Controlled synthesis and analysis of He–H 3 in a 3.7 K ion trap.
- Author
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Savić, Igor, Gerlich, Dieter, Asvany, Oskar, Jusko, Pavol, and Schlemmer, Stephan
- Subjects
HELIUM hydrides ,ION traps ,HELIUM at low temperatures ,GAS storage ,POTENTIAL energy surfaces - Abstract
Complexes of the triatomic hydrogen ion with helium were synthesised in a low-temperature 22-polerfion trap at He number densities of up to 1016cm−3. Absolute ternary rate coefficients for sequentially attaching He atoms have been determined from the growth of complexes with increasing storage time. The number of helium-tagged ions is significantly reduced when increasing the nominal temperature from 4 to 25 K. Competition between attachment and dissociation via collisions leads to stationary Hen–H+3(nup to 9) distributions. State-specific excitation of the trapped H+3ions via IR transitions significantly reduces the formation of complexes. Tuning the laser to Δv2= 1 transitions in the range of 2726 cm−1leads to LIICG lines, i.e., to spectra caused bylaser-induced inhibition of complex growth. In addition, almost 100 lines have been found between 2700 and 2765 cm−1, which are attributed tolaser-induced dissociationof thein situformed He–H+3complex ions. These lines are not yet assigned; however, their absorption strength, statistics and predissociation lifetimes provide interesting information on both the stable complexes as well as on scattering resonances in low-energy H+3+He collisions. New calculations of the potential energy surface will help to analyse the dissociation spectrum. There are some indications that para-H+3is enriched under the conditions of the present experiment. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
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13. Some Routes in Forming C3Hn+ Ions and Deuterated Variants under Interstellar Conditions.
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Savić, Igor and Gerlich, Dieter
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INTERSTELLAR molecules ,COSMOCHEMISTRY ,ASTROPHYSICAL collisions ,LOW temperatures ,HYDROGENATION ,DEUTERON reactions ,CHEMICAL reactions ,HYDROCARBONS - Abstract
Laboratory experiments on hydrogenation and deuteration of C
3 + , C3H+ and C3 H2 + in collisions with H2 and HD have been performed from room temperature down to 15 K using a 22-pole ion-trap. At room temperature C3 + reacts slowly with H2 but the reactivity increases with decreasing temperature. It has been shown that the association reaction C3 + + H2 → C3 H2 + + hν can compete with the exothermic reaction C3 + + H2 → C3 H+ + H. In collisions of C3 + with HD, formation of C3D+ is slightly favored over C3H+ formation. A pronounced competition between various channels has been detected for deuterated variants of the C3H+ + H2 system. Most surprising is that formation of C3HD+ is over one hundred times faster then formation of C3 H2 + in collisions of C3H+ and HD. An tentative explanation is that the H-HD exchange takes place via an open-chain H2CCCH+ intermediate. Reactions of C3 H2 + and C3 H3 + with H2 are very slow. The formation of C3H2D+ or C3 HD2 + and finally C3HD via dissociative recombination has been discussed. The reaction C3 H3 + + HD → C3 H2 D+ + H2 can be ignored in astrochemical models since the reaction rate at 15 K is very small; however, quite efficient routes have been found starting from C3 + and proceeding via deuterated C3H+ to C3 H2 + and C3 H3 + . The new reaction rate coefficients are recommended to be included in astrophysical databases. Nonetheless it is still unclear how to explain the large abundance of C3H2 and larger hydrocarbons and their deuterated variants observed in cold interstellar clouds. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]- Published
- 2006
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14. Photocatalytic application of bacterial-derived biopolymer in removing pharmaceutical contaminants from water.
- Author
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Bilić, Andrijana, Armaković, Sanja J., Savanović, Maria M., Zahović, Ida, Dodić, Jelena, Trivunović, Zorana, Savić, Igor, Gajo, Teodora, and Armaković, Stevan
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PHOTOCATALYTIC water purification , *WATER purification , *MOLECULAR structure , *POLLUTANTS , *BIOPOLYMERS - Abstract
The inadequate existence of practical techniques for water purification poses a prominent and widespread global environmental challenge. This study aims to clarify the efficacy of xanthan application in the photocatalytic removal of nadolol, pindolol, and cefoperazone from water reservoirs. Under the influence of a simulated solar light source, xanthan exhibited significant degradation rates for pindolol (77%) and cefoperazone (91%). In contrast, nadolol's degradation efficiency was notably lower (10%). These findings suggest that the molecular structure can substantially influence the efficiency of the purification process. Computational analyses were conducted to gain a more profound understanding of the implications of molecular structure. [Display omitted] • Biosynthesized xanthan in efficient photocatalytic water purification. • Effective emulsion stabilization and environmental remediation. • Computational analysis via DFT: RDG surface and quantum-molecular descriptors. • Paving the way for sustainable environmental cleanup strategy applications. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Istraživanja kompleksnih oblika spektralnih linija berilijuma u prisustvu berilijumske prašine
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Stankov, Biljana, Savić, Igor, Ivković, Milivoje, Djurović, Stevica, Obradović, Bratislav, and Gavanski, Lazar
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Optička emisiona spektroskopija ,izvori plazme ,plasma sources ,Optička emisiona spektroskopija, izvori plazme, spektralne linije berilijuma, berilijumska prašina, linije sa zabranjenim komponentama ,Optical emission spectroscopy, plasma sources, beryllium spectral lines, beryllium dust, spectral lines with forbidden comoponents ,spectral lines with forbidden comoponents ,beryllium dust ,spektralne linije berilijuma ,Optical emission spectroscopy ,linije sa zabranjenim komponentama ,beryllium spectral lines ,berilijumska prašina - Abstract
Opisani su detalji konstrukcije novog izvora plazme, u impulsnom režimu, konstruisanog za potrebe ekscitacija linija berilijuma u prisustvu berilijumske prašine. Konstrukcija izvora je ostvarena na takav način da je sprečeno prodiranje čestica prašine u atmosferu laboratorije. Opisane su dodatne 2 cevi za pražnjenje konstruisane od Al2O3 i SiO 2 . Pronađeni su i opisani optimalni uslovi za radizvora plazme. Vrednosti elektronske koncentracije, određene nakon maksimumastruje, korišćenjem vodonikove balmer beta linije, kreću se u opsegu 1,16-9,2 ∙1022 m -3 . Elektronska temperatura je određena na osnovu relativnih intenziteta linija dva uzastopna jonizaciona stanja istog elementa i kreće se u opsegu 10 500-15 500 K. Prikazane su snimljene linije berilijuma, osim rezonantnih. Dato je poređenje snimljenih linija sa postojećim teorisjkim podacima. Dve linije berilijuma koje se pojavljuju sa zabranjenom komponentom su prikazane prvi put. Pokazano je da postoji tipičan trend zavisnosti odnosa dozvoljene i zabranjene komponente, kao i rastojanja između položaja maksimuma intenziteta ove dve komponente, od elektronske koncentracije, koji se javlja kod linija sa zabranjenim komponentama, što govori omogućnosti ove linije za primenu u dijagnostici plazme., Construction details of new plasma source, running in pulsed regime, for beryllium spectral line studies, in the presence of beryllium dust particles are presented. The construction of the source was realised in such a way that it prevented the ingress of dust particles into the laboratory atmospher. Construction details andtesting of BeO discharge tube in comparison with SiO2 and Al2O3 discharge tubes are presented, also. Optimal conditions for plasma source operation and beryllium line studies are found. The electron density measured after discharge current maximum is determined from the peak separation of the hydrogen Balmer betaspectral line, and the electron temperature is determined from the ratios of the relative intensities of Be spectral lines emitted from successive ionized stages of atoms. Maximum values of electron density and temperature are measured to be 9.3∙1022 m -3 and 16 800 K, respectively. The recorded spectral lines of beryllium, other then resonant lines, are presented. The lines with forbidden component are described for the first time. The functional dependence of the wavelength separation range and peak intensity ratio of these lines uponelectron number density suggests the complex profile of the forbidden and allowed line, which can be used for diagnostics of low-temperature beryllium containing plasmas.
- Published
- 2020
16. Određivanje Starkovih poluširina spektralnih linija jonizovanog kiseonika i silicijuma, emitovanih iz plazme proizvedene u elektromagnetnoj udarnoj T-cevi
- Author
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Gavanski, Lazar, Djurović, Stevica, Mijatović, Zoran, Kuraica, Milorad, and Savić, Igor
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spectroscopy ,spectral line broadening ,Plazma ,spektroskopija ,shock waves ,Starkove poluširine ,Plasma, shock waves, ICCD camera, spectroscopy, spectral line broadening, Stark halfwidths ,Plasma ,udarni talasi ,širenje spektralnih linija ,Stark halfwidths ,Plazma, udarni talasi, ICCD kamera, spektroskopija, širenje spektralnih linija, Starkove poluširine ,ICCD camera ,ICCD kamera - Abstract
Ispitivana je zavisnost brzine fronta udarnih talasa u T-cevi od više parametara. Izvršeno je povezivanje ICCD kamere sa spektrometrom. Ispitane su karakteristike celokupnog sistema i izvršena je njegova optimizacija i kalibracija. Izmerene su Štarkove poluširine 45 spektralnih linija OII, 13 spektralnih linija Si II i 14 spektralnih linija Si III. Dobijene vrednosti su upoređene sa vrednostima koje se mogu naći u literature, kao i sa teorijskim vrednostima. Urađena je detaljna analiza rezultata iz ovog rada kao i svih dostupnih prethodno dobijenih eksperimentalnih podataka., The dependence of shock front velocity on different parameters was examined. The ICCD camera was mounted on the spectrometer. The characteristics of the whole system were examined and the system was optimized and calibrated. The Stark halfwidths of 45 O II spectral lines, 13 Si II spectral lines and 14 Si III spectral lines were measured. The obtained values were compared with the data available in the literature, as well as with theoretical values. A detailed analysis of both the experimental results given in this dissertation and previously published experimental data was done.
- Published
- 2017
17. The He-H 3 + complex. II. Infrared predissociation spectrum and energy term diagram.
- Author
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Salomon T, Brackertz S, Asvany O, Savić I, Gerlich D, Harding ME, Lipparini F, Gauss J, van der Avoird A, and Schlemmer S
- Abstract
The rotationally resolved infrared (IR) spectrum of the He-H
3 + complex has been measured in a cryogenic ion trap experiment at a nominal temperature of 4 K. Predissociation of the stored complex has been invoked by excitation of the degenerate ν2 mode of the H3 + sub-unit using a pulsed optical parametric oscillator system. An assignment of the experimental spectrum became possible through one-to-one correlations with bands of the spectrum theoretically predicted in Paper I [Harding et al., J. Chem. Phys. 156, 144307 (2022)]. 19 bands have been assigned and analyzed, and the energy term diagram of the lower states of this floppy molecular complex has been derived from combination differences (CDs) in the experimental spectrum. Ground state combination differences (GSCDs) reveal a large part of the energy term diagram for the He-H3 + complex in its vibrational ground state, v = 0. Experimental and theoretical term energies agree within experimental accuracy for the rotational fine structure associated with the total angular momentum quantum number J and the parity e/f as well as for the coarse spacing of the lowest K states of the complex. This favorable comparison shows that the potential energy surface (PES) calculated in Paper I is accurate. The barriers between the three equivalent global minima in this PES are relatively low and the He-H3 + complex is extremely floppy, with nearly unhindered internal rotation of the H3 + sub-unit. The resulting Coriolis interactions couple the internal and end-over-end rotation of the complex and contribute significantly to the energy terms. They are observed both in experiment and theory and are, e.g., the origin of different rotational constants for states of e and f parity. Also in this respect, experiment and theory agree very well. Despite the assignment and analysis of many bands of the extremely rich IR spectrum of He-H3 + , higher levels of excitation, including the complex stretching mode, need further attention.- Published
- 2022
- Full Text
- View/download PDF
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