BHPWAVE: An adiabatic gravitational waveform model for compact objects undergoing quasi-circular inspirals into rotating massive black holes

We present {bhpwave}: a new Python-based, open-source tool for generating the gravitational waveforms of stellar-mass compact objects undergoing quasi-circular inspirals into rotating massive black holes. These binaries, known as extreme-mass-ratio inspirals (EMRIs), are exciting mHz gravitational wave sources for future space-based detectors such as LISA. Relativistic models of EMRI gravitational wave signals are necessary to unlock the full scientific potential of mHz detectors, yet few open-source EMRI waveform models exist. Thus we built {bhpwave}, which uses the adiabatic approximation from black hole perturbation theory to rapidly construct gravitational waveforms based on the leading-order inspiral dynamics of the binary. In this work, we present the theoretical and numerical foundations underpinning {bhpwave}. We also demonstrate how {bhpwave} can be used to assess the impact of EMRI modeling errors on LISA gravitational wave data analysis. In particular, we find that for retrograde orbits and slowly-spinning black holes we can mismodel the gravitational wave phasing by as much as $\sim 10$ radians without significantly biasing EMRI parameter estimation.Comment: 24 pages, 17 figures, 2 table

Repeated faint quasinormal bursts in extreme-mass-ratio inspiral waveforms: Evidence from frequency-domain scalar self-force calculations on generic Kerr orbits

We report development of a code to calculate the scalar self-force on a scalar-charged particle moving on generic bound orbits in the Kerr spacetime. The scalar self-force model allows rapid development of computational techniques relevant to generic gravitational extreme-mass-ratio inspirals (EMRIs). Our frequency-domain calculations are made with arbitrary numerical precision code written in \textsc{Mathematica}. We extend spectral source integration techniques to the Kerr spacetime, increasing computational efficiency. We model orbits with nearly arbitrary inclinations $0\leq\iota<\pi/2$ and eccentricities up to $e \lesssim 0.8$. This effort extends earlier work by Warburton and Barack where motion was restricted to the equatorial plane or to inclined spherical orbits. Consistent with a recent discovery by Thornburg and Wardell \cite{ThorWard17} in time-domain calculations, we observe self-force oscillations during the radially-outbound portion of highly eccentric orbits around a rapidly rotating black hole. As noted previously, these oscillations reflect coupling into the self-force by quasinormal modes excited during pericenter passage. Our results confirm the effect with a frequency-domain code. \emph{More importantly, we find that quasinormal bursts (QNBs) appear directly in the waveform following each periastron passage.} These faint bursts are shown to be a superposition of the least-damped overtone (i.e., fundamental) of at least four ($l=m \le 4$) quasinormal modes. Our results suggest that QNBs should appear in gravitational waveforms, and thus provide a gauge-invariant signal. Potentially observable in high signal-to-noise ratio EMRIs, QNBs would provide high-frequency components to the parameter estimation problem that would complement low-frequency elements of the waveform.Comment: 28 pages, 11 figures, 5 tables; Updated to reflect published versio

Numerical and analytical models of self-force effects in Kerr extreme-mass-ratio inspirals

Ground-based detectors now regularly observe the merger of stellar-mass compact objects and their gravitational waves. Building on this success, ESA, in partnership with NASA, will launch the space-based LISA observatory to detect milli-Hertz gravitational wave signals. Extreme-mass-ratio inspirals (EMRIs)---binaries composed of a stellar-mass compact object orbiting a massive black hole---are ideal gravitational wave sources for LISA. Because of their unique properties, EMRIs can provide new insights concerning the growth of massive black holes (and their host galaxies) and enable the most precise tests of general relativity. To achieve this science, LISA will rely on accurate EMRI models to search for and analyze gravitational wave signals. The most accurate EMRI models rely on a mechanism known as the gravitational self-force to calculate an EMRI inspiral and the resulting gravitational waveform. For EMRIs with rotating (Kerr) massive black holes, current gravitational self-force calculations are too computationally demanding to be incorporated into full EMRI models. For my dissertation, I built a developmental scalar self-force code to devise and implement new numerical and analytical techniques for calculating self-force effects in Kerr spacetime. I introduce spectral techniques for numerically evaluating Kerr geodesics and the sources of scalar perturbations. I discuss how these methods can be extended to gravitational self-force calculations. With this code, I produced the first calculations of the scalar self-force along resonant and non-resonant inclined, eccentric orbits in Kerr spacetime. With these new resonant calculations I provided one of the first tests of the integrability conjecture, which holds for these scalar self-force results. I also uncovered the existence of a physical effect in EMRI waveforms, now referred to as quasinormal bursts. Quasinormal bursts are periodic high-frequency oscillations in EMRI waveforms which may aid in the characterization of EMRI gravitational wave sources.Doctor of Philosoph

DEVELOPMENT OF A METHOD FOR THE DETERMINATION OF THE BLUE DYE IN GAS OILS BY HYPHENATED NP-HPLC/DAD SYSTEM

U zemljama EU provodi se markiranje i bojanje goriva kako bi se razlikovala goriva različitih poreznih razreda. Fiskalni marker prisutan u gorivu ne mijenja boju goriva i određuje se referentnom metodom Europske unije za određivanje euromarkera (Solvent Yellow 124) u plinskom ulju (metoda tekućinske kromatografije visoke djelotvornosti, HPLC uz UV/DAD detekciju)1. Dodavanjem plave boje gorivu mijenja se značajno boja te je moguće trenutačno razlikovanje od boje čistog goriva. U laboratoriju se sadržaj markera SY 124 analizira u loživom ulju ekstra lakom i plavom dizelu tekućinskom kromatografijom visoke djelotvornosti. Određivanje sadržaja i količine plave boje u uzorcima plavog dizela koji se koristi u poljoprivredi, ribolovu i akvakulturi tekućinskom kromatografijom interesantno je s istraživačkog aspekta i s aspekta budućeg mogućeg praćenja zakonske regulative. U radu je opisan razvoj metode određivanja plave boje Solvent Blue 35 u uzorcima plavog dizela simultano uz određivanje euromarkera te problemi i izazovi pri kvantifikaciji.In the EU countries a system is in place for marking and coloring fuel to distinguish different fuel tax class. Fiscal marker present in fuel does not change the color of fuel and it is determined by the reference method for the determination of the European Union euromarker (Solvent Yellow 124) in gas oil (method of high performance liquid chromatography, HPLC with detection by UV / DAD) 1. By adding the blue dye to a fuel it changes color significantly and it is possible to immediately distinguish the colored from uncolored fuels. In the laboratory the content of SY 124 marker is analyzed in extra light fuel oil (LUEL) and diesel blue (EU DG PL) by HPLC method. Analyses are performed on an Agilent liquid chromatography system 1100, and a column packed with silica gel is used for separation. For the mobile phase, a mixture of toluene and ethyl acetate is used in the system. The paper describes the development of a method for the determination of the blue dye in gas oil samples simultaneously with the determination of the marker, as well as problems and challenges of quantification

Resonant self-force effects in extreme-mass-ratio binaries: A scalar model

Extreme-mass-ratio inspirals (EMRIs), compact binaries with small mass-ratios , will be important sources for low-frequency gravitational wave detectors. Almost all EMRIs will evolve through important transient orbital resonances, which will enhance or diminish their gravitational wave flux, thereby affecting the phase evolution of the waveforms at relative to leading order. While modeling the local gravitational self-force (GSF) during resonances is essential for generating accurate EMRI waveforms, so far the full GSF has not been calculated for an -resonant orbit owing to computational demands of the problem. As a first step we employ a simpler model, calculating the scalar self-force (SSF) along -resonant geodesics in Kerr spacetime. We demonstrate two ways of calculating the -resonant SSF (and likely GSF), with one method leaving the radial and polar motions initially independent as if the geodesic is nonresonant. We illustrate results by calculating the SSF along geodesics defined by three -resonant ratios (1∶3, 1:2, 2∶3). We show how the SSF and averaged evolution of the orbital constants vary with the initial phase at which an EMRI enters resonance. We then use our SSF data to test a previously proposed integrability conjecture, which argues that conservative effects vanish at adiabatic order during resonances. We find prominent contributions from the conservative SSF to the secular evolution of the Carter constant , but these nonvanishing contributions are on the order of, or less than, the estimated uncertainties of our self-force results. The uncertainties come from residual incomplete removal of the singular field in the regularization process. Higher order regularization parameters, once available, will allow definitive tests of the integrability conjecture

The Scaffold attachment factor b1 (Safb1) regulates myogenic differentiation by facilitating the transition of myogenic gene chromatin from a repressed to an activated state

The regulation of skeletal muscle gene expression during myogenesis is mediated by lineage-specific transcription factors in combination with numerous cofactors, many of which modify chromatin structure. However, the involvement of scaffolding proteins that organize chromatin and chromatin-associated regulatory proteins has not extensively been explored in myogenic differentiation. Here, we report that Scaffold attachment factor b1 (Safb1), primarily associated with transcriptional repression, functions as a positive regulator of myogenic differentiation. Knockdown of Safb1 inhibited skeletal muscle marker gene expression and differentiation in cultured C2C12 myoblasts. In contrast, over-expression resulted in the premature expression of critical muscle structural proteins and formation of enlarged thickened myotubes. Safb1 co-immunoprecipitated with MyoD and was co-localized on myogenic promoters. Upon Safb1 knockdown, the repressive H3K27me3 histone mark and binding of the Polycomb histone methyltransferase Ezh2 persisted at differentiation-dependent gene promoters. In contrast, the appearance of histone marks and regulators associated with myogenic gene activation, such as myogenin and the SWI/SNF chromatin remodelling enzyme ATPase, Brg1, was blocked. These results indicate that the scaffold protein Safb1 contributes to the activation of skeletal muscle gene expression during myogenic differentiation by facilitating the transition of promoter sequences from a repressive chromatin structure to one that is transcriptionally permissive

SEPARATION AND CHROMATOGRAPHIC ANALYSIS OF GAS OIL

Poznavanje detaljnog ugljikovodičnog sastava plinskog ulja dobivenog iz visbreaking procesa, koji se koristi za umješavanje u dizelsko gorivo, važno je za predviđanje kvalitete i ekoloških svojstava krajnjeg komercijalnog produkta. Plinsko ulje je kompleksna smjesa različitih grupa ugljikovodika: parafina, naftena, olefina, aromata, polarnih spojeva. Njihov ukupni sadržaj i međusobni odnos diktiraju konačna primjenska i ekološka svojstva. Za određivanje ugljikovodičnog sastava često se primjenjuju instrumentalne analitičke tehnike, među kojima dominiraju različite kromatografske tehnike (HPLC, GC, GC/MS, TC). Potpuna separacija ugljikovodičnih grupa vrlo se teško postiže zbog broja komponenata u pojedinoj grupi kao i zbog njihovog strukturnog sastava. Predfrakcionacijom plinskog ulja HPLC tehnikom na silikagel koloni modificiranoj srebrnim ionima, zasićeni ugljikovodici separirani su od ukupnih nezasićenih ugljikovodičnih grupa. Separirane frakcije analizirane su dalje tekućinskom kromatografijom visoke djelotvornosti normalnih faza (NP HPLC) uz detekciju na UV/DAD detektoru.Knowing the detailed hydrocarbon composition of the gas oil from visbreaking process used for blending of diesel fuel is very important for foreseeing the final commercial product quality and its ecological properties. Gas oil is complex mixture of different hydrocarbon groups: paraffines, naphtenes, olefins, aromatics, polar compounds. Their total content and relation control final product ecological and quality properties. Different chromatographic techniques (HPLC, GC, GC/MS, TLC) were used for determination of hydrocarbon composition in oil products. Complete hydrocarbon group separation is hard to reach because of the numerous components in one specific group and complex structure composition. HPLC prefractionation step of gas oil was performed on the in-house made silver – modified silica gel column. On silver column unsaturated hydrocarbons retain longer than saturated due to double-bond π electrons. By fractionation saturated and unsaturated fraction was separated and further analysed by normal – phase high performance liquid chromatography hyphenated by UV/DAD detection

Advanced analytical techniques - supporting the development of biofuels and alternative fuels

Potreba za razvojem alternativnih goriva i biogoriva potencirana je potrebom smanjenja utjecaja globalnog zagrijavanja i klimatskih promjena na planet te ograničenim resursima sirove nafte i prirodnog plina. Zadnjih godina pojavljuje se niz različitih vrsta biogoriva i alternativnih goriva različitog porijekla. Biogoriva su ekološki prihvatljiva alternativna goriva proizvedena od životinjskih i biljnih sirovina, a u svrhu razvoja biogoriva koriste se otpadni materijali iz proizvodnje drva, otpadne sirovine životinjskog porijekla, otpadna jestiva ulja te sirovine biomasa poput biljke Miscanthusa X giganteus, kukuruza, zobena slama, pšenična slama, soja, ječam i dr. Razvoj novih vrsta goriva prati razvoj novih i učinkovitijih analitičkih postupaka za praćenje sastava i svojstava. Stoga se često pri analizi biogoriva i alternativnih goriva koriste spektroskopske i kromatografske metode, samostalno ili u kombinacijama s drugim ispitnim metodama. Prednosti ovih metoda su velika osjetljivost, selektivnost i preciznost.The need to develop alternative fuels and biofuels has become essential regarding the need for reducing the impact of global warming and climate change on the planet as well as the limited resources of crude oil and natural gas. In recent years, different types of biofuels and alternative fuels of different origins have been developed. Biofuels are environmentally friendly alternative fuels produced from animal or plant origins. For biofuel development different materials like waste materials from wood production, waste raw materials of animal origin, waste edible oils and biomass raw materials such as miscanthus X giganteus, corn, oat straw, wheat straw, soybeans, barley are used. The development of new types of ecological friendly fuels goes with the development of new and more efficient analytical procedures for both monitoring the fuel composition and properties. Spectroscopic and chromatographic methods, either alone or in combination with other test methods, are often used in the analysis of biofuels and alternative fuels. The advantages of these methods are sensitivity, selectivity, and precision