Cluster decay dynamics of Actinides yielding non-Pb-daughter

The cluster dynamics of radioactive nuclei decaying to neighbouring daughter nuclei of the double magic $^{132}$Sn and $^{208}$Pb is investigated using the relativistic mean-field (RMF) approach with NL3$^*$ parameter set within the preformed cluster-decay model (PCM). The novel feature of the present study is the application of the newly derived preformation formula, laying the groundwork for accessing the break-up of the Q-value: preformation energy, cluster emission energy and the recoil energy of the daughters formed. The energy associated with cluster preformation is theoretically quantified for the first time. This treatment underscores the shell effect, pairing correlation as well as the blocking of particular orbitals by unpaired nucleons. To ascertain the applicability of the new formula, the PCM based calculations are carried out with nuclear potential obtained using the phenomenological M3Y and microscopic RMF-based R3Y nucleon-nucleon (NN) potentials along with corresponding densities. We found a marginal variation that can be attributed to the difference in their barrier properties, however, the predictions for the case of both M3Y and R3Y potentials are found to agree well with the experimental half-lives. Although none of the considered reaction systems yields a double magic daughter nucleus, we found that the kinematics of their cluster emissions is governed by their proximity to the shell closure. The deduced systematic of the recoil energy in cluster decays can provide valuable insight for the synthesis of elements in superheavy mass region in the future.Comment: 10 pages, 5 figures, Journa

Quest for a Universal Cluster Preformation Formula: A new paradigm for estimating the cluster formation energy

This study presents a holistic picture of the preformation of nuclear clusters with credence to the kinematics of their emissions. Besides the fitting of the preformation formula to reproduce the experimental half-lives, we have investigated the interrelationship between the parameters involved in the cluster decay process for medium, heavy and superheavy nuclei. Based on the established conceptual findings, we propose a new cluster preformation probability ($P_0$) formula that incorporates all influential parameters of the cluster radioactivity and thus has an edge over the existing formulae in the literature. Further, we hypothesize that a fraction of the decay energy is needed for cluster formation within the parent nucleus. The proposed formula opens a new paradigm to separately estimate the energy contributed during the cluster formation from its emission and thus shows that the contribution of the Q-value splits into three major parts accounting for the energy contributed during the cluster preformation, its emission and recoil of the daughter nucleus. Moreover, the expression $P_0$ is adept at accommodating the theorized concept of heavy particle radioactivity (HPR). The result reveals that, like $\alpha$-decay, a proper estimation of the $P_0$ and $Q$-value in the cluster studies are enriched with qualitative information about the nuclear structure. However, from the analysis, the Geiger-Nuttall law is not the best compromise in the clustering due to the non-linearity between $\log_{10}T_{1/2}$ and $\sqrt{Q}$, unlike in $\alpha$-decay. We have demonstrated that with the inclusion of the proposed formula, the half-life predictions from both microscopic R3Y and phenomenological M3Y NN potentials closely agree with the available experimental data and that the slight variation can be traced to their peculiar barrier characteristics.Comment: 7 pages, 3 figures, Journa

Role of Mothers\u27 Nutritional Knowledge, Nutritional Factors on the School Performance

A cross sectional study was carried out to investigate the effects of mothers\u27 nutritional knowledge, health and nutritional factors and socio-economic parameters on school performance among class five students of University Laboratory School, Dhaka. All of the eighty students were selected for this study. This study found there is a strong relationship between mother\u27s knowledge score and school performance. It was found that mothers\u27 knowledge score was responsible for 91.1 percent change in school performance. The mean BMI of the mothers was 20.44. We found that the school performance measured by class roll number of the students is significantly related with mothers BMI. There was an imperfect negative association between socio-economic parameters and school performance. But the relationship between the school performances with socio-economic parameters was strongly significant. This study also observed the relationship between Individual Dietary Diversity Score (IDDS) of respondent and marks achieved in class 4 final exam. It is alarming that consumption percentage were low for eggs (30) and milk and milk products (37.5), but majority of the students who consumed milk and milk products (63.3%) and eggs (66.7%) got the highest marks

Preformation Probability and Kinematics of Clusters Emission yielding Pb-daughters

In the present study, the newly established preformation formula is applied for the first time to study the kinematics of the cluster emission from various radioactive nuclei, especially those decaying to the double-shell closure $^{208}$Pb nucleus and its neighbours as daughters. The recently proposed universal cluster preformation formula has been established based on the concepts that underscore the influence of the mass and charge asymmetry ($\eta_A$ and $\eta_Z$), cluster mass $A_c$ and the Q-value, paving the way to quantify the energy contribution during the preformation as well as the tunnelling process separately. The cluster-daughter interaction potential is obtained by folding the relativistic mean-field (RMF) densities with the recently developed microscopic R3Y using the NL$3^*$ and the phenomenological M3Y NN potentials to compare their adaptability. The penetration probabilities are calculated from the WKB approximation. With the inclusion of the new preformation probability $P_0$, the predicted half-lives from the R3Y and M3Y interactions are in good agreement with the experimental data. Furthermore, a careful inspection reflects slight differences in the decay half-lives, which arise from their respective barrier properties. The $P_0$ for the systems with the double magic shell closure $^{208}$Pb daughter are found to be relatively higher with an order of $\approx 10^2$ than those with neighbouring Pb-daughter nuclei. By exploring the contributions of the decay energy, the recoil effect of the daughter nucleus is appraised, unlike several other conjectures. Thus, the centrality of the Q-value in the decay process is demonstrated and re-defined within the preformed cluster-decay model. Besides, we have introduced a simple and intuitive set of criteria that governs the estimation of recoil energy in the cluster radioactivity.Comment: 09 Pages, 06 Figures, and 01 Tabl

Water disinfection with geopolymer-bentonite composite foam containing silver nanoparticles

Geopolymers resemble conventional ceramics but can be manufactured at near-ambient temperatures. In this work, geopolymer-bentonite composite foam with silver nanoparticles was prepared and applied for water disinfection, inspired by point-of-use ceramic water filters. The inactivation efficiency against Escherichia coli and intestinal enterococci bacteria was found to be promising (0.6-2.4 and 0.3-1.4 log(10) reductions, respectively) for similar to 1 d. However, the inactivation efficiency against somatic coliphage viruses was poor (Peer reviewe

Correlation between the nuclear structure and reaction dynamics of Ar-isotopes as projectile using the relativistic mean-field approach

This theoretical study is devoted to bridging the gap between the nuclear structure and reaction dynamics and unravelling their impact on each other, considering the neutron-rich light mass 30-60Ar isotopes. Using the relativistic mean-field with the NL3* parameter set, several bulk properties such as binding energies, charge radii, quadrupole deformation parameter, two neutron separation energy, and differential two neutron separation energy with the shell closure parameter are probed for the mentioned isotopic chain. For validation, the RMF (NL3*) results are compared with those obtained from the finite range droplet model (FRDM), Weizsacker-Skyrme model with WS3, WS* parameters and the available experimental data. Most of the participating isotopes are found to be prolate in structure and neutron shell closures are conspicuously revealed at N=14, 20, 40 but weakly shown at N=24, 28, 34. From our analysis, a central depletion in the nucleonic density is identified in 32Ar and 42-58Ar, indicating them as possible candidates for a semi-bubble-like structure. Interestingly, these results are consistent with recent theoretical and experimentally measured data. Besides, using the Glauber model, the reaction cross-sections are determined by taking 26-48Ar as projectiles and stable targets such as 12C, 16O, 40Ca, 90Zr, 124,132Sn, 208Pb and 304120. Although there is no experimental evidence for the stability of 304120, it has been predicted in Ref. [Mod. Phys. Lett. A {\bf 27}, 1250173 (2012)] as a stable nucleus. A relatively higher cross-section value is noticed between 30Ar and 32Ar which infers that 32Ar is the most stable isotope among the considered chain. Moreover, we noticed that the profile of the differential cross-sections and scattering angle are highly influenced by the mass of the target nuclei and the magnitude of the incident energy of the projectile nucleus.Comment: 19 pages, 7 figure