Recovery of plutonium from aqueous waste solutions using porous zirconia spherical particles

Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of ¹³⁵Xe and ¹³³Xe, as well as the correlations of ¹³⁵Xe and ⁸⁸Kr activities.     

233Pa(2nth, f ) cross-section determination using a fission track technique

The νp process is a primary nucleosynthesis process which occurs in core-collapse supernovae. An essential role in this process is being played by electron antineutrinos. They generate, by absorption on protons, a supply of neutrons which, by (n, p) reactions, allow to overcome waiting point nuclei with rather long beta-decay and proton-capture lifetimes. The synthesis of heavy elements by the νp process depends sensitively on the $\bar \nu _e$ luminosity and spectrum. As has been shown recently, the latter are affected by collective neutrino flavor oscillations which can swap the $\bar \nu _e$ and $\bar \nu _{\mu ,\tau }$ spectra above a certain split energy. Assuming such a swap scenario, we have studied the impact of collective neutrino flavor oscillations on the νp-process nucleosynthesis. Our results show that the production of light p-nuclei up to mass number A = 108 is very sensitive to collective neutrino oscillations.     

Magnetic, magnetocaloric, and magnetotransport properties of RCo1.8Mn0.2 (R=Er, Ho, Dy, and Tb) compounds

The magnetic, magnetocaloric, and magnetotransport properties of RCo_1.8Mn_0.2 (R=Er, Ho, Dy, and Tb) were studied by room temperature X-ray diffraction, magnetization, and resistivity measurements at a temperature interval of 5-400 K and magnetic fields up to 5 T. The Curie temperature of RCo₂ was found to increase significantly when 10% Mn was substituted for Co. The effective paramagnetic moments were found to be in reasonable agreement with their theoretical values. A large magnetoresistance (MR) of Δρ/ρ_o≈−13.5% for R=Ho at T≈153 K for ΔH=5 T has been observed. The maximum relative cooling capacities vary from 467 J/kg at low temperature for R=Er to 202 J/kg at the near room temperature for R=Tb.     

Two source emission behavior of projectile fragments alpha in 84Kr interactions at around 1 GeV per nucleon

The emission of projectile fragments alpha has been studied in ⁸⁴Kr interactions with nuclei of the nuclear emulsion detector composition at relativistic energy below 2 GeV per nucleon. The angular distribution of projectile fragments alpha in terms of transverse momentum could not be explained by a straight and clean-cut collision geometry hypothesis of Participant — Spectator (PS) Model. Therefore, it is assumed that projectile fragments alpha were produced from two separate sources that belong to the projectile spectator region differing drastically in their temperatures. It has been clearly observed that the emission of projectile fragments alpha are from two different sources. The contribution of projectile fragments alpha from contact layer or hot source is a few percent of the total emission of projectile fragments alphas. Most of the projectile fragments alphas are emitted from the cold source.     

Gauging universe expansion via scalar fields

In this study, we investigate the expansion of the FRLW universe in the open, closed, and flat geometries. The universe is dominated by a scalar field (spatially homogeneous) as a source of dark energy. We consider the three different classes of scalar fields – quintessence, tachyonic, and phantom field – for our analysis. A mathematical analysis is carried out by considering these three scalar fields with exponential and power-law potentials. Both potentials give exponential expansion in the open, closed, and flat FRLW universes. It is found that quintessence, tachyonic, and phantom scalar fields are indistinguishable under the slow roll approximation.     

Mathematical modeling of solvent extraction of uranium from sulphate media employing 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A) and its mixture with trioctylphosphine oxide (TOPO) as extractants

The extraction of U(VI) from sulphate medium with 2-ethylhexyl phosphonic acid-mono-2-ethylhexyl ester (PC88A, H₂A₂ in dimeric form) in n-dodecane has been investigated under varying concentrations of sulphuric acid and uranium. Slope analysis of uranium (VI) distribution data as a function of PC88A concentration suggests the formation of monomeric species, viz. UO₂(HA₂)₂. This observation was further supported by the mathematical expression obtained during non-linear least square regression analysis of U(VI) distribution data correlating the percentage extraction (%E) and the acidity (H _i). A mathematical model correlating the experimental distribution ratio values of U(VI) (D _U) with initial acidity (H _i) and initial uranium concentrations (C _i) was developed: D_\textU = 12.98( ±0.90)/{ C_\texti ^{- 0.75( ±0.05)} ×[ H_\texti ]² } D_{\text{U}} = 12.98( \pm 0.90)/\left\{ {C_{\text{i}}^{ - 0.75( \pm 0.05)} \times \left[ {H_{\text{i}} } \right]^{2} } \right\} . This expression can be used to predict the concentration of uranium in organic as well as in aqueous phase at any C _i and H _i. The extraction data were used to calculate the conditional extraction constant (K _ex) values at different acidities (2–7 M H⁺), uranium (0.02–0.1 M) and PC88A (0.2–0.6 M) concentrations. These studies were also extended for the extraction of U(VI) using synergistic mixtures of PC88A and TOPO from sulphate medium.     

An insight into our research on vinyl sulfone-modified pyranosides and furanosides

This review describes the research by the authors on the synthesis of vinyl sulfone-modified carbohydrates and the application of this new class of Michael acceptors in the generation of a wide range of aminosugars, branched-chain sugars, cyclopropanted carbohydrates, densely functionalized cyclopropanes, isonucleosides and pyrroles.     

Triazole-linked-thiophene conjugate of calix[4]arene: its selective recognition of Zn2+ and as biomimetic model in supporting the events of the metal detoxification and oxidative stress involving metallothionein

Supramolecular calix[4]arene conjugate (L) has been developed as a sensitive and selective sensor for Zn(2+) in HEPES buffer among the 12 metal ion by using fluorescence, absorption and ESI MS and also by visual fluorescent color. The structural, electronic, and emission properties of the calix[4]arene conjugates L and its zinc complex, [ZnL], have been demonstrated using ab initio density functional theory (DFT) combined with time-dependent density functional theory (TDDFT) calculations. The TDDFT calculations reveal the switch on fluorescence behavior of L is mainly due to the utilization of the lone pair of electrons on imine moiety by the Zn(2+). The resultant fluorescent complex, [ZnL], has been used as a secondary sensing chemo-ensemble for the detection of -SH containing molecules by removing Zn(2+) from [ZnL] and forming {Cys/DTT·Zn} adducts as equivalent to those present in metallothioneins. The displacement followed by the release of the coordinated zinc from its Cys/DTT complex by heavy metal ion (viz. Cd(2+) and Hg(2+)), as in the metal detoxification process or by ROS (such as H(2)O(2)) as in the oxidative stress, has been well demonstrated using the conjugate L through the fluorescence intensity retrieval wherein the fluorescence intensity is the same as that observed with [ZnL], which in turn mimics the zinc sensing element (MTF) in biology.