11. Search for ▫$Z^\prime \to \mu^+ \mu^-$▫ in the ▫$L_\mu - L_\tau$▫ gauge-symmetric model at BelleT. Czank, Karol Adamczyk, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Manca Mrvar, Rok Pestotnik, Tomaž Podobnik, Samo Stanič, Marko Starič, Luka Šantelj, 2022, izvirni znanstveni članek Opis: We search for a new gauge boson Z′ that couples only to heavy leptons and their corresponding neutrinos in the process e+e−→Z′(→μ+μ−)μ+μ−, using a 643 fb−1 data sample collected by the Belle experiment at or near the Υ(1S,2S,3S,4S,5S) resonances at the KEKB collider. While previous searches for Z′ performed a data-based estimation of the initial state radiation effect, our search for the Z′ is the first to include effects due to initial state radiation in the signal simulated samples that were used in estimating the detection efficiency. No signal is observed in the Z′ mass range of 0.212–10 GeV/c2, and we set an upper limit on the coupling strength, g′, constraining the possible Z′ contribution to the anomalous magnetic dipole moment of the muon.
Ključne besede: Extensions of gauge sector, leptonic, semileptonic & radiative decays
Objavljeno v DKUM: 25.09.2023; Ogledov: 455; Prenosov: 29
 Celotno besedilo (725,14 KB)
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12. Potential of using waste materials in flexible pavement structures identified by optimization design approachPrimož Jelušič, Süleyman Gücek, Bojan Žlender, Cahit Gürer, Rok Varga, Tamara Bračko, Murat V. Taciroğlu, Burak E. Korkmaz, Şule Yarcı, Borut Macuh, 2023, izvirni znanstveni članek Opis: This paper presents the design of geosynthetic reinforced flexible pavements and their modification by incorporating waste materials into bonded and unbonded layers of the pavement structure. The optimal design of flexible pavements was achieved by minimizing the construction cost of the pavement. The incorporation of waste materials into the pavement structure affects the material properties. Therefore, along with the traffic load, the effects of the material properties of the asphalt concrete, base layer, sub-base layer, and subgrade were analyzed in terms of pavement structure costs and CO2 emissions of materials used in pavement construction. In addition, a comparison was made between pavements with and without geosynthetic reinforcement in terms of design, optimum construction cost, and CO2 emissions. The use of geosynthetics is even more effective in pavement structures that contain waste materials in an unbound layer, both in terms of cost and CO2 emissions. The minimum value of the California Bearing Ratio of the subgrade was determined at which the use of geosynthetic reinforcement for pavement structure with and without the inclusion of waste materials is economically and sustainably justified. The use of geosynthetics could result in a 15% reduction in pavement structure cost and a 9% reduction in CO2 emissions due to the reduced thickness of unbound layers. In addition, reducing the CBR of the unbound layer from 100% to 30% due to the inclusion of waste materials implies a cost increase of up to 13%. While the present study is based on an empirical pavement design method in which pavement thickness is limited by the pavement thickness index, the same minimum thicknesses are obtained in the optimization process regardless of whether the objective function is the minimum construction cost or minimum CO2 emissions.
Ključne besede: pavement design, waste materials, optimization, minimum construction cost, CO2 emissions, geosynthetics, waste management
Objavljeno v DKUM: 18.09.2023; Ogledov: 644; Prenosov: 51
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13. Measurement of two-particle correlations of hadrons in ▫$e^+ e^-$▫ collisions at BelleY.-C. Chen, Marko Bračko, Samo Korpar, Peter Križan, Tomaž Podobnik, Marko Starič, Luka Šantelj, 2022, izvirni znanstveni članek Opis: The measurement of two-particle angular correlation functions in high-multiplicity e+e− collisions at √s=10.52 GeV is reported. In this study, the 89.5 fb−1 of hadronic e+e− annihilation data collected by the Belle detector at KEKB are used. Two-particle angular correlation functions are measured in the full relative azimuthal angle (Δϕ) and three units of pseudorapidity (Δη), defined by either the electron beam axis or the event-shape thrust axis, and are studied as a function of charged-particle multiplicity. The measurement in the thrust axis analysis, with mostly outgoing quark pairs determining the reference axis, is sensitive to the region of additional soft gluon emissions. No significant anisotropic collective behavior is observed with either coordinate analyses. Near-side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various event generators and are expected to provide new constraints to the phenomenological models in the low-energy regime.
Ključne besede: Particle & resonance production, Quark & gluon jets, Quark-gluon plasma
Objavljeno v DKUM: 24.08.2023; Ogledov: 396; Prenosov: 9
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14. Implementation of climate change effects on slope stability analysisTamara Bračko, Bojan Žlender, Primož Jelušič, 2022, izvirni znanstveni članek Opis: The objective of this study is to determine the impacts of expected climate change on slope stability. For this purpose, the case study of a slope instability, that was triggered in 2021 was selected. The stability analysis was performed considering the theory of rainfall infiltration and using Geo-Studio’s SEEP/W module for the surface infiltration model of the slope. A parametric stability analysis of the slope was conducted to determine the importance of climate change on slope stability. Conditions for changes in volumetric water content, water permeability, porewater pressure, and groundwater flow are important. When soil permeability is low, the factor of safety decreases during rainfall events and on the days following, while when permeability is higher, safety increases after rainfall events. The effect of lower cohesion is nearly linear, with the factor of safety decreasing by 0.1 for every 1 kPa less cohesion. The increase in net infiltration of water may be the most critical factor for slope instability. The results of the analysis indicate that timely reduction of water net infiltration through planting and proper surface water runoff from the upper road and slope would be a relatively simple and inexpensive measure compared to the cost of remediating the landslide, considering expected climate change. Therefore, it is advisable to analyze all slopes with respect to the expected climate change, taking into account the potential impacts of climate change.
Ključne besede: climate change adaptation, slope stability, rainfall infiltration, water net infiltration, seepage analyses
Objavljeno v DKUM: 18.08.2023; Ogledov: 478; Prenosov: 68
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15. Measurement of the branching fraction and ▫$CP$▫ asymmetry for ▫$B \to \bar{D}^0 \pi$▫ decaysT. Bloomfield, Jyoti Prakash Biswal, Marko Bračko, Samo Korpar, Peter Križan, Rok Pestotnik, Tomaž Podobnik, Marko Starič, Luka Šantelj, 2022, izvirni znanstveni članek Opis: We measure the branching fractions and CP asymmetries for the decays B⁰ → D¯ 0π⁰ and B⁺ → D¯ 0π⁺, using a data sample of 772 × 10⁶ BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e⁺e− collider. The branching fractions obtained and direct CP asym-metries are B(B⁰ → D¯ 0π⁰)=[2.70 0.06(stat) 0.10(syst)]×10−⁴, B(B⁺ → D¯ 0π⁺)=[4.53 0.02(stat) 0.15(syst)]×10−³, ACP(B⁰ → D¯ 0π⁰)= [+0.42 2.05(stat) 1.22(syst)]%, and ACP(B⁺ → D¯ 0π⁺) = [+0.19 0.36(stat) 0.57(syst)]%. The measurements of B are the most precise to date and are in good agreement with previous results, as is the measurement of ACP(B⁺ → D¯ 0π⁺). The measurement of ACP for B⁰ → D¯ 0π⁰ is the first for this mode, and the value is consistent with Standard Model expectations.
Ključne besede: branching fraction, hadronic decays, particle decays, mesons, CP violation, precision measurements
Objavljeno v DKUM: 17.08.2023; Ogledov: 364; Prenosov: 39
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16. Search for the decay ▫$B_s^0 \to \eta \eta$▫S. Bhuyan, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Rok Pestotnik, Marko Starič, Luka Šantelj, 2022, izvirni znanstveni članek Opis: We report results from a search for the decay B0s→ηη using 121.4 fb−1 of data collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We do not observe any signal and set an upper limit on the branching fraction of 14.3×10−5 at 90% confidence level. This result represents a significant improvement over the previous most stringent limit.
Objavljeno v DKUM: 17.08.2023; Ogledov: 270; Prenosov: 32
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17. Vibracijski in rotacijski prehodi enostavnih molekul : magistrsko deloMatic Orel, 2022, magistrsko delo Opis: V magistrskem delu obravnavamo rotacijske in vibracijske prehode molekul. Molekulsko
dinamiko bomo opisali z analitiˇcnimi metodami, zato se bomo omejili na dovolj preproste
molekule z dobro definirano simetrijo. Pravilnost izraˇcunov bomo preverili z obiˇcajnimi
raˇcunalniˇskimi orodji, ki se v kemiji uporabljajo za prikaz in opis molekulske dinamike.
Namen magisterskega dela je bilo preveriti, do kam lahko pridemo z analitiˇcnim pristopom
pri obravnavi infrardeˇce spektroskopije manjˇsih molekul z enostavnimi simetrijami.
Izkazalo se je, da je to izredno zahteven postopek, kateri zahteva tako znanje kemije kot
tudi teorije grup. V tem delu smo predstavili ter uporabili nastavke za izraˇcun najpomembnej
ˇsih parametrov, kateri vplivajo na intenzitete v infrardeˇcem spektru, t.j. spinska
statistiˇcna uteˇz za dane irreducibilne specije spinske valovne funkcije ter energije rotacij
oz. vibracij ˇzeljene molekule. S pomoˇcjo ter dveh parametrov smo pri dani temperaturi
zapisali Boltzmannovo enaˇcbo infrardeˇcega spektra ter s prikazali odsek le-tega. Primera
vode ter CHF3 sta bila skrbno izbrana zaradi razliˇcnih simetrijskih lastnosti (asimetriˇcni
vs. simetriˇcni rotor, 2 protona vs. 3 protoni itd.) ter zaradi relativne enostavnosti
izraˇcunov. V zakljuˇcku smo predstavili ˇse dodatne aspekte analitiˇcne analize, katerim bi
se lahko posluˇzili t.j. spremembe simetrije molekule ob substituciji tipa atoma, teˇzave z
relativistiˇcnim nadaljevanjem ter karakterizacija elektronske valovne funkcije preko LCAO
ansazt-a.
Ključne besede: Molekulska dinamika, vibracije in rotacije molekul, molekulska simetrija, infrardeˇca spektroskopija, resonanˇcne frekvence, raˇcunski program Gaussian
Objavljeno v DKUM: 20.05.2022; Ogledov: 749; Prenosov: 68
Celotno besedilo (3,98 MB) |
18. Pomen in razvoj eksplozivne in vzdržljivostne (repetitivne) moči pri nogometašihNejc Bračko, 2022, diplomsko delo Opis: Namen diplomskega dela je predstaviti, kako se razvija moč pri nogometaših in kakšen
pomen ima pri igranju nogometa. V teoretičnem delu predstavljamo moč na splošno,
opisujemo vrste moči, poglobljeno obravnavamo vzdržljivostno in eksplozivno moč,
prikazujemo metode dela ter nekaj vaj z žogo in brez nje, s katerimi lahko dosežemo
želeni napredek pri razvoju moči. Z raziskavo smo ugotovili, da rezultati pri eksplozivni
moči niso odvisni od pozicije igralca, kar pomeni, da igralci na napadalno usmerjenih
pozicijah nimajo boljših rezultatov pri merjenju eksplozivne moči in tudi igralci na
obrambno usmerjenih pozicijah ne boljših rezultatov pri merjenju vzdržljivostne moči.
Poleg navedenega smo tudi ugotovili, da vzdržljivostna moč in kratki šprint nista
statistično značilno povezana, kar pomeni, da igralci, ki imajo visoko eksplozivno moč,
nimajo tudi visoke vzdržljivostne moči. Statistično značilno povezanost smo ugotovili le
med eksplozivno močjo in kratkim šprintom, vendar tudi tukaj samo delno. Statistično
značilna povezanost s kratkim šprintom se je pokazala pri drugem skoku z levo in drugem
skoku z desno nogo, medtem ko pri ostalih kazalnikih eksplozivne moči, to je pri prvem
skoku z levo nogo, prvem skoku z desno nogo in pri obeh skokih sonožno, statistično
značilne povezave nismo zaznali.
Ključne besede: nogomet, eksplozivna moč, repetitivna moč
Objavljeno v DKUM: 31.03.2022; Ogledov: 1218; Prenosov: 152
Celotno besedilo (2,08 MB) |
19. Modelno zasnovano vodenje sinhronskega motorja z delno implementacijo na CLA koprocesorski enoti krmilnikov družine C2000 : magistrsko deloMatic Bračko, 2022, magistrsko delo Opis: V magistrskem delu je predstavljeno modelno snovanje algoritma za vodenje motorjev za obstoječi elektromehanski pretvornik AEK, ki bo vgrajen na električno kolo. Za potrebe preizkusa algoritma smo pripravili simulacijski model sistema električnega kolesa, s katerim smo preizkusili ustreznost izbranih komponent, kot tudi robustnost in zanesljivost delovanja zasnovanega algoritma. Po uspešni simulaciji smo delovanje algoritma preizkusili še na preizkuševališču. Z namenom pospeševanja računanja algoritma za vodenje motorja smo del algoritma prestavili na CLA (Control Loop Accelerator) enoto uporabljenega digitalnega signalnega krmilnika Texas Instruments TMS320F28069, nameščenega v pretvorniku, s čimer smo sprostili glavno procesorsko jedro za časovno manj kritične operacije.
Ključne besede: FOC, FW, CLA, SVM, IPMSM
Objavljeno v DKUM: 14.02.2022; Ogledov: 816; Prenosov: 0 |
20. Vpliv dodajanja enoloških taninov v različnih fazah alkoholne fermentacije na fizikalno-kemijske lastnosti vina sorte 'modri pinot'Urška Bračko, 2020, magistrsko delo Opis: Proučevali smo vpliv dodajanja treh enoloških taninov (Protanin R, Gallotanin B, Galitan Agrovin) v različnih fazah alkoholne fermentacije grozdnega soka (na začetku fermentacije, med njo in na koncu fermentacije) sorte 'Modri pinot' na vsebnost skupnih fenolov, antocianinov, taninov, mineralov ter nianso in intenziteto barve vina. Na povišanje vsebnosti skupnih fenolov je značilno vplival dodatek Gallotanina B, ki smo ga dodali med fermentacijo. Vsebnost taninov se je v primerjavi s kontrolnim vzorcem značilno zvišala ob dodatku Gallotanina B in Galitan Agrovin na koncu alkoholne fermentacije. Čas dodajanja taninov in vrsta tanina sta vplivala na nianso barve vina, na vsebnost antocianinov in na intenziteto barve vina. Najvišja vsebnost antocianinov je bila v vzorcu s Protaninom R, dodanim med alkoholno fermentacijo, kjer je bila tudi niansa barve najvišja. Največja intenziteta barve pa je bila v vzorcu s Protaninom R, ki smo ga dodali na koncu fermentacije.Vsebnost Mn, Fe in Zn v vinu je bila odvisna od časa dodajanja taninov, vsebnost Fe pa tudi od vrste dodanega tanina.
Ključne besede: enološki tanini/ antocianini/ 'Modri pinot'/ barva/ minerali
Objavljeno v DKUM: 16.06.2020; Ogledov: 1415; Prenosov: 144
Celotno besedilo (1,34 MB) |
