We calculate the signal rate of hypothetical heavy neutral leptons (HNL or sterile neutrinos) from kaon decays expected in the framework of the SHiP experiment. The kaons are produced in the hadronic ...shower initiated in the beam-dump mode by 400 GeV protons from CERN SPS. For a sufficiently light HNL (when the decays are kinematically allowed) we find kaon decays to be a noticeably richer source of HNL as compared to D-meson decays adopted in previous studies of the HNL phenomenology at SHiP. In particular, SHiP is capable of fully exploring the central part of the kinematically allowed region of the HNL mass and mixing with electron and muon neutrinos down to the lower cosmological bound. The latter is associated with HNL decays in the early Universe to energetic products rescattering off and thus destroying light nuclei produced at the primordial nucleosynthesis. A consistency of the HNL model with smaller mixing would require either a hierarchy – much larger mixing of all the HNL with tau neutrino – or non-standard cosmology and new ingredients in the HNL sector, closing the room for the minimal non-seesaw type I model with sterile neutrinos lighter than kaons.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We argue that the fixed target experiment PS191 operating on a proton beam of 19.2 GeV at CERN in the eighties was sensitive to hypothetical light scalars produced by mesons and decaying to charged ...particles. The experiment was dedicated to searches for sterile neutrinos produced in weak meson decays and decaying into final states with pairs of charged particles: electrons and muons. Two charged tracks from the same point have been adopted as the signal signature. Exploiting the same signature we use the negative results of searches at PS191 and place new limits on the light scalars coupled to the Standard Model (SM) particles via mixing with the Higgs boson. In particular, previously allowed region of masses 100–150 MeV and mixing above 4×10−4 is disfavored. Our analysis can be extended straightforwardly to models with other patterns of scalar couplings to SM particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We perform Monte Carlo simulations of the sterile neutrino signal at the fixed target experiment PS191 operated on a proton beam of 19.2GeV at CERN in the eighties. We find that the strongest bounds ...the PS191 could obtain are significantly lower than what they published, and now are obsolete being surpassed by recent T2K, NA62, E949, TRIUMF and PIENU experiments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We calculate the production of hypothetical millicharged particles (MCPs) of sub-GeV masses by the J-PARC proton beam in the framework of T2K and future T2HK neutrino oscillation experiments. ...Concentrating on the region of model parameter space, where an MCP can hit the near neutrino detector twice, we adopt this background-free signature to estimate the sensitivity of T2K and T2HK experiments to MCPs. We find that a previously inaccessible in direct searches region of charges 5×10−4-10−2e for MCP masses 0.1-0.5 GeV can be probed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A mesoporous silica support was synthesized using the sol-gel method from trichlorosilane. There is a tendency for the specific surface area and the proportion of silica particles mesopores to ...increase during all stages of sol-gel synthesis. It has been shown that the insertion of hexane and toluene, as additional solvents, into the structure-forming polyethylene glycol, makes it possible to regulate the pore size and specific surface area of silica. Silica functionalization was carried out using SILP technology. The activities of the catalytic systems based on polymer and inorganic supports immobilized by imidazole-based ionic liquids during the trichlorosilane disproportionation reaction were compared. There is a tendency for the monosilane yield for catalytic systems based on an inorganic support to increase. We identified the most promising catalyst in terms of monosilane yield and proposed a bifunctional catalyst that exhibited activity in two parallel reactions: trichlorosilane disproportionation and silicon tetrachloride hydrogenation.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The present paper deals with the complex study of CO
capture from combined heat power plant flue gases using the efficient technological design of a membrane cascade type of «Continuous Membrane ...Column» for binary gas mixture separation. In contrast to well-known multi-step or multi-stage process designs, the cascade type of separation unit provides several advantages. Here, the separation process is implemented in it by creating two counter current flows. In one of them is depleted by the high-permeable component in a continuous mode, meanwhile the other one is enriched. Taking into account that the circulating flows rate overcomes the withdrawn one, there is a multiplicative increase in separation efficiency. A comprehensive study of CO
capture using the membrane cascade type of «Continuous Membrane Column» includes the determination of the optimal membrane material characteristics, the sensitivity study of the process, and a feasibility evaluation. It was clearly demonstrated that the proposed process achieves efficient CO
capture, which meets the modern requirements in terms of the CO
content (≥95 mol.%), recovery rate (≥90%), and residual CO
concentration (≤2 mol.%). Moreover, it was observed that it is possible to process CO
with a purity of up to 99.8 mol.% at the same recovery rate. This enables the use of this specific process design in CO
pretreatment operations for the production of high-purity carbon dioxide.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Trace H2O to C2H2 conversion on CaC2 in NH3 matrix was studied for GC-FID analysis.•HOCaCCH intermediate formation is assumed and its presence is proved by CaC2 FTIR.•Side reaction rate and the ...condition of CaC2 affect the measurement reproducibility.•Optimal range of ammonia sample flow rates is important for CaC2/GC-FID measurements.•GC-FID moisture analysis is comparable to FTIR by accuracy, but less resource-intensive.
The current study focuses on the processes involved during the flow conversion of water into acetylene in a calcium carbide reaction cell for the trace moisture analysis of ammonia by reaction gas chromatography. The factors negatively affecting the reproducibility and the accuracy of the measurements are suggested and discussed. The intramolecular reaction of the HOCaCCH intermediate was found to be a side reaction producing background acetylene during the contact of wet ammonia gas with calcium carbide. The presence of the HOCaCCH intermediate among the reaction products is confirmed by an FTIR spectral study of calcium carbide powder exposed to wet gas. The side reaction kinetics is evaluated experimentally and its influence on the results of the gas chromatographic measurements is discussed in relation to the determination of the optimal operating parameters for ammonia analysis. The reaction gas chromatography method for the trace moisture measurements in an ammonia matrix was experimentally compared to an FTIR long-path length gas cell technique to evaluate the accuracy limitations and the resource intensity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Herein, we report for the first time a study dedicated to acidic gases’ solubility in ionic liquids with sterically hindered bulky anion, namely bis(2-ethylhexyl) sulfosuccinate (doc), experimentally ...evaluated at low pressures. The effect of cation change (imidazolium, pyridinium, and pyrrolidinium) on the thermophysical properties and sorption capacities was also discussed. The densities and the activation energies of the tested ILs exhibited minor differences. Furthermore, the COSMO-RS model was used to predict the free volumes of ILs aiming to investigate its influence on gas solubilities. The conducted calculations have revealed an antibate correlation between the fractional free volume (FFV) and Henry’s law constant. In particular, the lowest FFV in 1-methylimidazolium doc corresponded to the minimal sorption and vice versa. In addition, it was shown that the presence of protic cation results in a significant reduction in CO2 and H2S solubilities. In general, the solubility measurement results of the synthesized ILs have shown their superiority compared to fluorinated ILs based on the physical absorption mechanism.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The present work discusses IR spectroscopic experiments and quantum- chemical DFT study of structure and intermolecular binding in the intermediate gas?liquid systems of aromatics, namely, benzene, ...furane, pyridine and thiophene. These systems can be generated in thin layers near a solid surface by two different methods, depending on the physical properties of the sample. The first method includes evaporation with a subsequent compression of a sample in an optical cell of variable thickness, and it is applied to volatile components: benzene, furane, thiophene. For benzene and pyridine the second method is used, which involves a heating-initiated evaporation into a closed inter-window space with an after-cooling of a sample. It was shown that the formed layer is not an adsorbate or a condensate. The IR data obtained by these two methods lead to conclusion that the given systems of the considered aromatics manifest dual gas?liquid spectral properties which can change each into other by varying external conditions. According to the DFT calculation results, the spatial arrangement in the aromatic thin layers can be described as a combination of ?- and ?-bonded clusters, which simulate the gas and the liquid phase state properties.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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