557 research outputs found
The Brans–Dicke–Rastall theory
No full textWe formulate a theory combining the principles of scalar–tensor gravity and Rastall’s proposal of a violation of the usual conservation laws. We obtain a scalar–tensor theory with two parameters and , the latter quantifying the violation of the usual conservation laws ( corresponding to the General Relativity limit). The only exact spherically symmetric solution is that of Robinson–Bertotti besides the Schwarzschild solution. A PPN analysis reveals that General Relativity results are reproduced when . The cosmological case displays a possibility of deceleration/acceleration or acceleration/deceleration transitions during the matter dominated phase depending on the values of the free parameters
FROM NEO-INDUSTRIAL REVOLUTION TO NEO-INDUSTRIAL DEVELOPMENT
No full textIn respect to innovations in production resources the author designed STR-organization of neo-industrial production, which includes pace maximization, pace method of selecting machines, universalization and STR-synchronization of production process (PP). It was found that PP universalization causes innovations in production resources which withdraw manual labour from production sphere and relocate it to the service sphere and improve the quality and productivity of mental labour. The article describes the model of non-industrial development designed by the author which shows that: 1) innovation in capital resources and STR- organization of the production process lead to singling out and concentration of enterprises outputting the aggregate row of end products (object universalization), aggregate row of product knot by one or several technologies (knot object and knot technological universalization) that carry out by different technologies the same stage of technological process (stage-by-stage technological universalization); 2) STR-organization of PP envisages parallel production of PP sections, the absence of unfinished production, rejecting the fixed work time and use of work time as a regulator of the production volume taking into account the demand; 3) innovation in costs (operational and cyclic costs) causes the dependence of active capital and material costs on the quantity of output product and obtaining depreciation profit while consuming capital
Open Mic with LISA: Intermediate-Mass Black Holes and Double White Dwarfs
No full textThe Laser Interferometer Space Antenna (LISA) is a space gravitational wave (GW) detector that will operate in the frequency band 0.1–1,000 mHz. As a GW detector, LISA is not a directional instrument. Instead, it can be thought of as a big “microphone” that will be recording a myriad of GW “sounds” at the same time. Among those are the voices of two rich yet scarcely known populations we focus on in this work: intermediate-mass black holes (IMBHs) and Galactic double white dwarfs (DWDs).
First, we show that it is possible to use LISA for indirect detection of IMBHs in the Milky Way if they are orbited by binaries emitting GWs in the LISA band. The GW signal from the binary around an IMBH will undergo a Doppler modulation which may reveal the presence of the IMBH. We find that the globular cluster (GC) Omega Centauri, which is long suspected to host an IMBH, is the most promising candidate for a positive detection with this method.
Second, we investigate a scaled-up version of the three-body systems considered above, in which the supermassive black hole (SMBH) in our Galactic Center is orbited by an IMBH paired with a stellar-mass object. We demonstrate that the induced Doppler modulation can then be used to constrain the presence of IMBHs with masses 1,000–100,000 solar masses at a distance of 0.1–2 milliparsecs from the SMBH.
Third, we focus on the quasimonochromatic nature of the Galactic DWDs: the fact that, for many of them, the GW frequency drift during the LISA observation time ∆f ≲ 1/yr. We revisit the stationary-phase approximation (SPA) widely used in estimating measurement uncertainties in the frequency domain (FD), and we show how the conventional SPA must be modified for consistent results.
Finally, we investigate whether the Galactic DWDs can be used to probe the Milky Way’s large-scale gravitational field. While it is unlikely to measure the respective center-of-mass accelerations with GWs alone, combining GW and electromagnetic (EM) observations can make the measurement possible. We also propose an efficient implementation of the Fisher matrix calculations which makes use of auto-differentiation.
In this thesis we focus on papers [1–4] where the author made major contributions. To a lesser extent, the author also contributed to papers [5–7] over the course of the PhD program
Open Mic with LISA: Intermediate-Mass Black Holes and Double White Dwarfs
No full textThe Laser Interferometer Space Antenna (LISA) is a space gravitational wave (GW) detector that will operate in the frequency band 0.1–1,000 mHz. As a GW detector, LISA is not a directional instrument. Instead, it can be thought of as a big “microphone” that will be recording a myriad of GW “sounds” at the same time. Among those are the voices of two rich yet scarcely known populations we focus on in this work: intermediate-mass black holes (IMBHs) and Galactic double white dwarfs (DWDs).
First, we show that it is possible to use LISA for indirect detection of IMBHs in the Milky Way if they are orbited by binaries emitting GWs in the LISA band. The GW signal from the binary around an IMBH will undergo a Doppler modulation which may reveal the presence of the IMBH. We find that the globular cluster (GC) Omega Centauri, which is long suspected to host an IMBH, is the most promising candidate for a positive detection with this method.
Second, we investigate a scaled-up version of the three-body systems considered above, in which the supermassive black hole (SMBH) in our Galactic Center is orbited by an IMBH paired with a stellar-mass object. We demonstrate that the induced Doppler modulation can then be used to constrain the presence of IMBHs with masses 1,000–100,000 solar masses at a distance of 0.1–2 milliparsecs from the SMBH.
Third, we focus on the quasimonochromatic nature of the Galactic DWDs: the fact that, for many of them, the GW frequency drift during the LISA observation time ∆f ≲ 1/yr. We revisit the stationary-phase approximation (SPA) widely used in estimating measurement uncertainties in the frequency domain (FD), and we show how the conventional SPA must be modified for consistent results.
Finally, we investigate whether the Galactic DWDs can be used to probe the Milky Way’s large-scale gravitational field. While it is unlikely to measure the respective center-of-mass accelerations with GWs alone, combining GW and electromagnetic (EM) observations can make the measurement possible. We also propose an efficient implementation of the Fisher matrix calculations which makes use of auto-differentiation.
In this thesis we focus on papers [1–4] where the author made major contributions. To a lesser extent, the author also contributed to papers [5–7] over the course of the PhD program
Preparation of vanilla extracts and characterization of components
No full textVanilija je dragocena in redka tropska rastlina, ki uspeva samo na določenih pordročjih. Njeni plodovi za zorenje potrebujejo od 7 do 9 mesecev, nakar sledi še skoraj polletni postopek \u27\u27sušenja\u27\u27 (angl. curing). Med sušenjem plodovi oziroma stroki razvijejo značilno aromo vanilije, ki je svetovno ena najbolj prepoznavnih in uporabljenih.
Zaradi same redkosti, dolgotrajnega procesa pridobivanja in obdelave, je cena vaniljevih strokov visoka. Temu primerno je za industrijo zelo pomembno optimizirati pogoje pridobivanja vaniljevega ekstrakta, ocenitev njegove kvalitete in tudi obstojnosti.
Pred uporabo vaniljevih strokov kot surovine, je potrebno preveriti njihovo kvaliteto oziroma sestavo, ki je zelo odvisna od geografskega področja rasti in obdelave. V ta namen smo določili optimalne pogoje ekstrakcije po Soxhletu in z ultrazvokom, s čimer smo pridobili laboratorijsko reprezentativne ekstrakte kot predoceno in kriterij sprejemljivosti za industrijski proces.
Za analizo pridobljenih ekstraktov, smo v nalogi razvili in validirali metodo tekočinske kromatografije. Z njo smo kvalitativno in kvantitativno spremljali ključne komponente vaniljevega ekstrakta (vanilin, p-hidroksibenzaldehid, p-hidroksibenzojska kislina in vanilinska kislina). Razvita metoda nudi hiter in kakovosten vpogled v sestavo vaniljevega ekstrakta.
Z metodo plinske kromatografije (HS-SPME) smo spremljali tudi hlapne komponente v vaniljevih strokih, s čimer dobimo vpogled predvsem v starost strokov. Slednje smo nadgradili z identifikacijo in primerjavo hlapnih komponent v svežih strokih in strokih, ki smo jih izpostavili neprimernim skladiščnim pogojem. Identificiranim komponentam smo dodali senzorični opis in stopnja vpliva na senzorični profil.
Za zaključek smo s tekočinsko kromatografijo spremljali tudi obstojnost pripravljenih vaniljevih ekstraktov pri različnih skladiščnih pogojih.Vanilla is a valuable and rare tropical plant that thrives only in specific regions. Its fruits require 7 to 9 months to ripen, followed by an almost six months long process of "curing." During the curing process, the fruits or pods develop the characteristic vanilla aroma, which is one of the most recognizable and widely used scents globally.
Due to its rarity and the time intensive process of cultivation and processing, the price of vanilla pods is high. Consequently, it is very important for the industry to optimize the conditions for extracting vanilla extract, assess its quality, and ensure its stability.
Before using vanilla pods as raw materials, their quality and composition must be checked, as these depend significantly on the geographical area of cultivation and processing. For this purpose, we determined the optimal extraction conditions using the Soxhlet method and ultrasound, obtaining laboratory representative extracts as a preliminary assessment and a criterion of acceptability for the industrial process.
For the analysis of the obtained extracts, we developed and validated a liquid chromatography method. This method was used to qualitatively and quantitatively monitor the key components of vanilla extract (vanillin, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, and vanillic acid). The developed method provides a fast and high quality insight into the composition of vanilla extract.
Using gas chromatography (HS-SPME), we also monitored volatile components in vanilla pods, which primarily give insight into the age of the pods. This was further enhanced by identifying and comparing volatile components in fresh pods and pods exposed to inappropriate storage conditions. Identified components were supplemented with sensory descriptions and their impact on the sensory profile.
Finally, we used liquid chromatography to monitor the stability of prepared vanilla extracts under various storage conditions
Stiffness and strength characteristics research of a vibration-isolating pipe based on modeling
No full textThe double-resonance enhancement of stimulated low-frequency Raman scattering in silver-capped nanodiamonds
No full textObservation of a New Xi(-)(b) Resonance
No full textFrom samples of pp collision data collected by the LHCb experiment at √s = 7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and
1.5 fb[superscript −1], respectively, a peak in both the Λ[superscript 0][subscript b]K[superscript −] and Ξ[superscript 0][subscript b]π[superscript −] invariant mass spectra is observed. In the quark model, radially and orbitally excited Ξ[superscript −][subscript b] resonances with quark content
bds are expected. Referring to this peak as Ξ[subscript b](6227)[superscript −], the mass and natural width are measured to be m[subscript Ξ
[subscript b]](6227)[superscript −] = 6226.9 ± 2.0 ± 0.3 ± 0.2 MeV/c[superscript 2] and Γ[subscript Ξ[subscript b]](6227)[superscript −] =
18.1 ± 5.4 ± 1.8 MeV/c[superscript 2], where the first uncertainty is statistical, the second is systematic, and the third, on m[subscript Ξ[subscript b]](6227)
[superscript −], is due to the knowledge of the Λ[superscript 0][subscript
b] baryon mass. Relative production rates of the Ξ[subscript b](6227)[superscript −] → Λ[superscript 0][subscript b]K[superscript −] and Ξ[subscript b](6227)[superscript −] → Ξ[superscript 0][subscript b]π[superscript −] decays are also reported
Convection flow optimization in online hemodiafiltration
No full textObjective: to evaluate the dependence of the magnitude of convection flow in online hemodiafiltration (OLHDF) on ultrafiltration control method and patients’ individual characteristics. Materials and methods. The study included 36 stable dialysis patients (20 male and 16 female). The substitution rate was conducted manually based on transmembrane pressure (TMP). In some cases, devices with automatic filtration rate control unit AutoSub plus were used. The filtration rate (FR), TMP, blood flow rate (Qb), specific filtration rate (SFR, m/l/min/mm Hg–1 ) were recorded. Results. The maximum SFR in various patients ranged from 0.51 to 0.80 ml/min/mm Hg–1 ; average value was 0.62 ± 0.07 ml/min/mm Hg–1 . There was significant correlation of SFR with hemoglobin level (r = –0.55). SFR reduced during hemodiafiltration (on average – by 23 ± 4%). SFR was significantly affected by Qb (r = 0.70). Maximum SFR was achieved with a TMP of 140–220 mm Hg; with TMP over 250 mm Hg, a decrease in SFR was noted, an increase in Qb was required for further increase in FR. Individual stability of SFR was noted during serial observations; fluctuations in a particular patient did not exceed 10%. Substitution volume for the HDF session was 18.0 ± 3.3 L, the FR/Qb ratio was 24.7 ± 5.2%. Substitution volume of 21 L was not achieved in 17 of 36 patients. The use of automatic FR adjustment system made it possible to increase the substitution volume (SV) by 12–18%. Conclusion. Achieving maximum convection volume in OLHDF requires individualizing treatment parameters. The use of FR automatic control allows maximum possible convection flow
First Observation of Excited Omega(-)(b) States
No full textWe report four narrow peaks in the Ξb0K- mass spectrum obtained using pp collisions at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb-1 recorded by the LHCb experiment. Referring to these states by their mass, the mass values are m[ωb(6316)-]=6315.64±0.31±0.07±0.50 MeV, m[ωb(6330)-]=6330.30±0.28±0.07±0.50 MeV, m[ωb(6340)-]=6339.71±0.26±0.05±0.50 MeV, m[ωb(6350)-]=6349.88±0.35±0.05±0.50 MeV, where the uncertainties are statistical, systematic, and the last is due to the knowledge of the Ξb0 mass. The natural widths of the three lower mass states are consistent with zero, and the 90% confidence-level upper limits are determined to be Γ[ωb(6316)-]<2.8 MeV, Γ[ωb(6330)-]<3.1 MeV and Γ[ωb(6340)-]<1.5 MeV. The natural width of the ωb(6350)- peak is 1.4-0.8+1.0±0.1 MeV, which is 2.5σ from zero and corresponds to an upper limit of 2.8 MeV. The peaks have local significances ranging from 3.6σ to 7.2σ. After accounting for the look-elsewhere effect, the significances of the ωb(6316)- and ωb(6330)- peaks are reduced to 2.1σ and 2.6σ, respectively, while the two higher mass peaks exceed 5σ. The observed peaks are consistent with expectations for excited ωb- resonances
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