[en] Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z = 82 and the neutron midshell at N = 104. Evidence for shape coexistence has been inferred from α-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Secondary, radioactive ion beams of "2"0"2Rn and "2"0"4Rn will be discussed by means of low-energy Coulomb excitation at the REX-ISOLDE in CERN. The results will be discussed in terms of collectivity and the deformation of both nuclei studied is deduced to be weak, as expected from the low-lying level-energy schemes. Comparisons will also be made to state-of-the-art beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced. (author)

[en] We discuss results and future plans for low-energy reactions that play an important role in current nuclear astrophysics research and that happen to concentrate around the region of A = 7. The ⁷Be(p,γ)⁸B and the ³He(⁴He,γ)⁷Be reactions are crucial for understanding the solar-neutrino oscillations phenomenon and the latter one plays a central role in the issue of cosmic ⁷Li abundance and Big-Bang Nucleosynthesis. The electron-capture (EC) decay rate of ⁷Be in metallic Cu host and the β^-decay rate of ¹⁹⁸Au in the host alloy Al-Au have been measured simultaneously at several temperatures, ranging from 0.350 K to 293 K. The resulting null temperature dependence is discussed in terms of the inadequacy of the often-used Debye-Hueckel model for such measurements

[en] Nanocomposite is a nanotechnology-based multiphase, high-performance composite material having combination of properties, which has been emerged as one of the promising research and development activities. Recently, nanocomposites have shown significant application opportunities for several sectors of biotechnology, engineering, and medical sciences, and its dispersed fluids (composite nanofluids) have gained huge interest and demand in wide area of engineering applications, particularly for heat transfer intensification. The main aim of the present review is to summarize the recent advances in nanocomposite-dispersed nanofluids. The synthesized methods, characterization, and applications of nanocomposites as well as the preparation, stability analysis, thermophysical, optical and electrical properties, heat transfer and pressure drop characteristics and applications of nanocomposite-dispersed nanofluids are well-grouped and discussed. Present review reveals that the nanocomposite with proper combination of nanomaterials yields superior performance characteristics compared to the individual alone for application in nanofluids, although many related aspects are still unexplored. Hence, the challenges and opportunities for future research are also identified, which will be useful for the newcomers and manufacturers in this field.

[en] In this paper, a new stage structured prey–predator model with Monod–Haldane functional response is proposed and the stages for predator have been considered. The proposed mathematical model consists of three nonlinear delay differential equations to describe the interaction among prey, immature predator and mature predator populations. Two time delays viz. feedback delay and gestation delay have been used as the bifurcation parameter. A rigorous mathematical analysis has been carried out by considering all possible cases for both the delays. Conditions for local stability and Hopf bifurcation have been investigated in all cases. Furthermore, by using normal form method, Riesz representing theory and central manifold theorem, formulae are derived for the direction of Hopf bifurcation and stability of bifurcating periodic solutions. Global stability analysis is carried out and the numerical simulation to validate the theory is also executed at the end.

[en] Intensity Modulated Radiotherapy (IMRT), Image guided Radiotherapy (IGRT), Volumetric Arc Therapy (VMAT/Rapid-Arc) delivery techniques deliver dose to the tumor in the complex intensity pattern. Quality assurance (QA) of complex dose distribution in patient necessitates comprehensive dosimetry systems which allows high resolution, precise and accurate measurement of dose distribution pre-treatment QA measurements: 2D arrays such as MapCHECK (Sun Nuclear), MatriXX"E"v"o"l"u"t"i"o"n (IBA Dosimetry) and OCTAVIOUS 1500 (PTW), 3D phantoms such as OCTAVIUS 4D (PTW), ArcCHECK (Sun Nuclear) and Delta4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDose™ (Sun Nuclear) and Dosimetry Check™ (Math Resolutions) are commercially available. These equipment consists of one or more measurement arrays of ion chambers and diodes. To estimate the delivered dose, different calculation algorithms are used to reconstruct a full 3D dose in the patient geometry. This makes the QA rely not only on the measurement but also on a calculation algorithm in the software. The independent validation studies on those algorithms are insufficient and there is a need for further studies. (author)

[en] The use of EBT3 Gafchrmoic film in radiotherapy gains popularity due to its easy processing and quick use. Machine QA, Invivo dosimetry, and patient specific quality assurance (PSQA) test for special procedures like SRS requires the use of GafChrmoic films. The calibration, processing and interpretation are mostly affected by user handling and discrepancies in the operating procedures. In this study, to mitigate/minimize such types of errors, ML based approaches is used to perform the analysis and interpretation of the gafchrmoic films for PSQA. ML models can be used an alternative and easy to use tool for prediction of the doses from the gafchromic film scanned images, This limitation of this study is simple assumptions to fit the model without taking into account complex procedure. This study can be further utilized for the patient specific quality assurance tests for special procedures

[en] In the recently developed high-sensitive CaSO₄:Dy phosphor, sieving before the high-temperature sintering treatment has successfully eliminated particle agglomeration during subsequent sintering, and has further enhanced its thermostimulated luminescence (TSL) sensitivity to γ-rays. The reduction in TSL sensitivity of higher sized grains observed earlier following the procedure of sieving after sintering has also more or less vanished. Maximum TSL sensitivity is seen after sintering around 700 deg. C, whereas maximum photoluminescent (PL) sensitivity is seen after sintering around 325 deg. C. While the observed increase in TSL sensitivity (by 30%) with increasing sintering temperature in the range 325-700 deg. C is explained on the basis of diffusion of Dy³⁺ ions from the surface to the whole volume of the grains (0-75 μm), the drastic decrease (by a factor of 3) in PL sensitivity with increasing sintering temperature is explained on the basis of change in the Dy³⁺ environment on the grain surface perhaps due to oxygen incorporation. Washing with water and acetone, which affect mainly the surface traps, enhances the PL sensitivity of CaSO₄:Dy slightly; however, it does not influence TSL sensitivity very significantly. Grinding reduces PL in general, but no such trend was noticed in TSL which supports the conclusion that PL originates mainly from surface traps since grinding affects mainly the grain surface. However, the sharp reduction in TSL and PL sensitivities observed at 400 deg. C indicates that an unusual process takes place near that sintering temperature. (author)

[en] This article presents finite element analysis to evaluate the performance of a compensated hydrostatic circular thrust pad bearing in the presence of a magnetic field. The influence of the magnetic field on the flow of an electrically conducting lubricant is expressed by incorporating the Lorentz force in the momentum equation, described by Maxwell equations and Ohm’s law. The modified Reynolds equation has been derived for a lubricant blended with long-chain polymer additives flowing in the presence of a transverse magnetic field. The Stokes couple stress theory has been used to describe effect of such additives on lubricant rheology. A source code has been developed in MATLAB to solve the modified Reynolds equation coupled with restrictor flow equations using the finite element method. The performance characteristics of the bearing system are evaluated in terms of pocket pressure, load-carrying capacity, lubricant flow rate, fluid film stiffness and damping coefficient. Comparative studies have been carried out for orifice and capillary compensated bearings. The limiting cases of the modified Reynolds equation yield performance characteristics of specific lubricants such as electrically conducting couple stress lubricant, couple stress lubricant, electrically conducting lubricant and Newtonian lubricant. It is noticed that the load-carrying capacity, fluid film stiffness and damping capabilities of the bearing get enhanced quite substantially in the presence of couple stress additives and a magnetic field.

[en] The nuclear spectroscopic quadrupole moments for the πh_9/25/2^-, 1/2^-[541] and the πh_11/29/2^-, 9/2^-[514] isomeric states in ¹⁶⁹Ta have been measured employing the time differential perturbed angular-distribution technique following the nuclear reaction ¹⁵⁹Tb(¹⁶O, 6nγ)¹⁶⁹Ta at beam energy 104 MeV. The ratio of the intrinsic quadrupole moments Q₀(K^π = 5/2^-)/Q₀(K^π = 9/2^-) has been derived as 1.87(13) from the measured quadrupole precession frequencies of the corresponding states. The model-independent analysis of the equilibrium deformation indicates strong prolate- and oblate-driving nature of the 1/2^-[541] and 9/2^-[514] orbitals in ^169,171Ta isotopes, respectively. (orig.)

[en] The spectroscopic quadrupole moments of the K^π = 8^- isomers in ¹⁷⁰Hf and ¹⁷²Hf, Q_s = 4.91(17) b and 5.40(19) b, respectively and Q_s = 4.92(17) b for K^π = 23/2^- in ¹⁷¹Hf have been measured using the time differential perturbed angular distribution technique. The nuclear reaction ¹⁶⁰Gd(¹⁶O, xnγ) was used to excite the respective isomeric states and for the recoil implantation of Hf nuclei into the Hf foil. The quadrupole deformation for the 8^- isomer and the ground state has the same value. The deformation corresponding to 23/2^- isomeric state is observed to be reduced with respect to the ground state due to the i_13/2 neutron alignment. The results are in good agreement with the multi-quasiparticle calculations.