We investigate the collective quantum dynamics of an ensemble of two-level emitters, embedded in a crystal, and coherently pumped by a moderately intense, and externally applied coherent electromagnetic field. The ensemble is damped preponderantly via the surrounding phonon reservoir which mediates the inter-particle collective interactions. We have found that generally phonon transitions among the corresponding dressed states are taking place involving simultaneously many single emitters or pairs of two-level emitters, respectively. In both cases the phonon intensity can be proportional to the squared number of involved two-level emitters.

We show that linear stability analysis not only describes the effect of modulation instability (MI) of a plane wave in nonlinear media but it also predicts significant wave amplification outside of the standard instability band. As an example, we consider the classic MI in the case of the nonlinear Schrödinger equation. However, similar amplification may take place in many other nonlinear media that admit modulation instability.

The aim of this paper is to generate a kind of integrable hierarchies of four-component evolution equations with Hamiltonian structures, from a kind of reduced Ablowitz-Kaup-Newell-Segur (AKNS) matrix spectral problems. The zero curvature formulation is the basic tool and the trace identity is the key to establishing Hamiltonian structures. Two examples of Hamiltonian equations in the resulting integrable hierarchies are added to the category of coupled integrable nonlinear Schrödinger equations and coupled integable modified Korteweg-de Vries equations.

This work rigorously presents the findings of entropy generation in Casson fluid flow on a Riga plate, exposed in a radiative environment. The conceptual basis for the investigation of fluid flow is the system of governing boundary layer equations. By means of implicit finite difference procedure the solutions of boundary layer equations are acquired. Primary goal of this study manifests the optimization of entropy generation in Casson fluid flow associated with EMHD (Electro Magneto Hydro Dynamics) Lorentz force and thermal radiation. Additionally, the contours of entropy generation and Bejan number are demonstrated. Validation of present results with previously obtained results from literature is accomplished conscientiously.

In this study, we experimentally investigate the variation of the phase matching condition of the high harmonic generation (HHG) process with pure argon gas and an argon-neon gas mixture. Phase-matched HHG is generated around the absorption edge of argon gas and then neon gas is added to the original argon gas. The pressure-dependent intensity of the harmonics produced by pure argon gas and the gas mixture is examined. We show that as more neon gas is added to the mixture, the phase matching of the higher order harmonics is less favourable than that of the lower order harmonics. Finally, the total phase mismatch at various gas mixture pressures is discussed. Our experimental results are in agreement with the theoretical calculation.

New features of the light localization in a nonlinear and graded-index medium in the case of radial symmetry are described analytically. The model of nonlinear graded-index fiber assumes that the dielectric permittivity changes abruptly when the electric field amplitude reaches a certain level. The dielectric permittivity depends on the polar radius according to a parabolic law, in the regions where the electric field amplitude exceeds a certain level. Explicit exact solution to the wave equation is found, in terms of the Whittaker function and the modified Bessel function of the second kind, describing a new type of optical localized structure. The influence of the propagation constant and parameters of the nonlinear graded-index dielectric permittivity on the field profile over the fiber radius is analyzed. It is derived that the core radius and the dielectric permittivity of the core depend on the propagation constant. The dependence of the core radius on the propagation constant causes the appearance of local dispersion.

Considering the Hulthén potential as the nuclear part of interaction regular solution is derived by exploiting the Frobenius method. The Jost function is constructed by utilizing its integral representation in terms of regular solution. The scattering phase shifts and cross-sections are calculated for the $n−^3$He system from the on-shell Jost function. The results obtained are in close conformity with the previous works that exist in the literature.

The paper presents results from computer simulations performed on a model of an RF electron source for the Laser Compton Scattering (LCS) γ-ray system. The new LCS γ-ray system is under implementation at ELI-NP/IFIN-HH. Different configurations of the system modelled with the ASTRA software package and different setings on the system components were analysed to optimize the inital beam parameters before acceleration up to ultra-relativistic energy in linac. The properly designed RF electron source contibutes significantly towards delivery a high brightness beam, which is a crucial specification for the LCS γ-rays systems.

Different empirical and theoretical methods are used to precisely determine radionuclide activity concentrations. This study used Monte Carlo simulation MCNP5 code and EFFTRAN software (Efficiency Transfer) to determine the HPGe detector Full-Energy Peak (FEP) efficiency. A set of point sources (¹³³Ba, ¹⁵²Eu, ¹³⁷Cs, ⁶⁰Co, and ²²Na) fixed on the top of the standard geometry plastic container were measured in order to obtain the calibration curve. Because of the importance of chemical composition parameters, the detector behavior due to different matrices was investigated. Experimental verification of the calibration was obtained using IAEA-TEL-2021-03 quality control water sample spiked with ¹⁵²Eu and ¹³³Ba, and the results were compared with reported results. A set of Certified Standard Reference samples were used for method validation. The obtained results were compared with the experimental results. The comparison clarified the advantages and disadvantages of both methods and their precision to demonstrate and suitable method for matrix types.

One alternative effort to eliminate the accumulation of transuranic (TRU) elements generated from LWR spent fuel is by utilizing TRU as nuclear fuel in pebble bed reactor. This work was aimed to investigate the neutronic behavior of a pebble bed reactor used for TRU transmutation. The reactor geometry is adopted from the HTR-Modul. MCNP6 multipurpose radiation transport code with ENDF/B-VII.1 neutron library was used to calculate the neutronic aspects. The results indicated that the initial effective multiplication factor (k_eff) values decrease as the amount of TRU fuel pebbles within the core increases, concurrent with the fuel burnup. Increasing the TRU fuel pebble ratio resulted in weakened Doppler temperature coefficients (DTCs) and improvement in moderator temperature coefficients (MTCs). The calculated total mass of plutonium and minor actinide transmutation demonstrated that a pebble bed reactor with 100% TRU pebble can reduce TRU mass up to 55.47% of its initial mass load.

Optical detection of alpha particle emitters in the environment by air radioluminescence is a new technology that enables sensing a radiological threat at safe distances, without putting personnel at risk or contaminating equipment. Radioluminescence detection systems need to be fine-tuned to efficiently capture a substantial number of photons while minimizing the contribution from ambient ultraviolet light. The accurate simulation of radioluminescence, in conjunction with ray tracing, facilitates the design and optimization of such detection systems. In this work, an application within the Geant4 framework has been developed to simulate radioluminescence photons emitted in the vicinity of accelerated alpha particles and at the surface of alpha radioactive samples. The application relies on existing scintillation physics implemented in Geant4 classes such as G4OpticalPhysics and G4Scintillation, which are used to simulate radioluminescence photons as scintillations produced during the passage of alpha particles through air. The application computes the ultraviolet image of alpha particles accelerated at energies of 5.1 MeV and 8.3 MeV, as well as an extended alpha source, M. Luchkov et al., Nucl. Instrum. Meth. Phys. Res. A 1047, 167895 (2023) [1]. The application enables optimization of experimental setups for various scenarios, such as radiological emergency management, radiological crime scene investigations, or decommissioning of nuclear facilities, thus minimizing the use of costly resources and exposure to radiation.

PEGylated PEIs are intensely studied non-viral vectors for gene delivery, having high transfection efficiencies. Using all-atom molecular dynamics simulations, the interaction of hyperbranched polyethylenimine polyethylene glycol (HPEI-PEG) with DNA was investigated for different number of PEG chains per HPEI core, and, to this end, a new CHARMM Force Field for PEG was developed. The obtained force field parameters are validated by the good agreement of structural measures, such as the radius of gyration, with experimental evidence.
The reported investigations reveal an upper bound for the PEG fraction in the modelled HPEI-PEG polymers. The addition of PEG reduces cytotoxicity, increases solubility, while still ensuring a high efficiency of forming polyplexes with DNA. Useful correlations between the copolymer structure and polyplex properties are observed, along with insights on the dynamics of the formation of hydrogen bonds between the HPEI core and DNA.

The magnetic properties and phase diagrams of a hexagonal nanotube with core-shell structure have been examined within the framework of the mean field theory based on the Bogoliubov inequality as well as the Monte Carlo simulation via the Metropolis algorithm. We have studied in detail the influences of the different exchange couplings and the crystal field on the phase diagrams of the system. This study allowed us to discover the existence of interesting critical phenomena, in particular the compensation behavior. Moreover, we have investigated the behavior of the magnetizations corresponding to each of the phase diagrams in order to verify the obtained results.

UV radiation can have a harmful effect on both humans and the environment. Therefore, developing UV shielding materials is an important step in protecting ourselves and the environment from the harmful effects of UV radiation. Here we present a detailed study of ZnO-SnO₂/PMMA nanocomposite coatings, which completely block UVC radiation. Additionally, we study the effect of the addition of ZnO-SnO₂ nanoparticles on mechanical properties in the means of Vickers microhardness and find out that they positively affect the microhardness of the PMMA coatings up to a certain concentration. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) reveal quite homogeneous distribution of nanoparticles for lower concentrations and the presence of nanoparticle aggregates for higher concentrations such as 1 wt.% and 5 wt.% of ZnO-SnO₂ nanoparticles.

This work explores the photovoltaic performance of a high efficiency heterostructure based on CIGS solar cells using SCAPS. Various electrical specifications were explored at various thicknesses and doping densities. Initially, photovoltaic characteristics of the ITO/GaSe/CIGS heterostructure are investigated. The results show an optimized PCE of 22.59%. Then, a thin film strongly doped p-type is employed
(CIGS-p⁺) to the structure. The engagement of the CIGS-p⁺ layer increases the PCE to 31.94%. The proposed CIGS-p⁺ layer is interpreted to serve as a back surface field. The structure is further improved by adding a third interfacial layer of p-MoS₂ transition metal dichalcogenide material between the absorber and the Mo back contact. Adding a third interfacial layer implied an efficiency increase of 34.55%. The results reveal that the MoS₂ layer at the CIGS/Mo interface adapts it creating Schottky-type contact to quasi-ohmic contact. The results confirm the beneficial influence of the interface layers on the CIGS heterostructure. Additionally, the performance of the photovoltaic cell against the defect intensity of the absorber layers is found to degrade behind a level of 1 ×
10¹⁸ cm^–3. An ITO/GaSe/CIGS/CIGS-p⁺ based structure exhibited the highest stability in performance against the temperature change among the three examined systems.

The aim of this paper is to identify mathematical correlations between the physical and geochemical properties of first quality limestone extracted from the Lower Globigerina Member. Based on published results, it can be confirmed that very strong correlations exist for (i) apparent density and uniaxial compressive strength when limestone is in a saturated condition, and (ii) ultrasonic pulse velocity – both perpendicular and parallel to the bedding plane – and uniaxial compressive strength when limestone is in either oven-dried or saturated conditions. Stronger correlation is present with respect to apparent density when limestone is oven-dried and color. The correlations for color and (a) ferric oxide, and (b) loss-on-ignition are also strong.

Application Specific Integrated Circuits (ASICs) have been, for a long time, the best, and sometimes only, option when there was a need for high performance electronics while operating with tight constraints regarding communication bandwidth, speed and/or latency, low power consumption and other, more specialized requirements, such as radiation hardness. To make sure that all ASICs that are going to be used in electronics parts installed on experimental physics detectors are working properly, they need to be thoroughly tested and their testing results need to be stored and used for manufacturing traceability purposes. A test bench solution which allows identifying and eliminating sources of errors during the integration of ASICs in detector electronics based on machine vision and test automation procedures has been designed for this purpose and is being presented.