Reaction dynamics studies for the system 7Be + 208Pb at Coulomb barrier energies

The scattering process of the Radioactive Ion Beam 7Be from a 208Pb target was measured at three near-barrier energies. The quasi-elastic angular distributions were analyzed within the framework of the optical model to extract the reaction cross sections. The results are compared with those obtained for the reactions induced by the mirror projectile 7Li and by the lightest particle-stable lithium isotope 6Li on the same target. The angular distributions for the production of the two 7Be constituent clusters, namely 3He and 4He, were also measured. In agreement with what observed for the interaction of 7Be with lighter targets, the production of the heavier helium isotope resulted to be much more abundant than that of its lighter counterpart

Some Archaeometrical Determinations on a Lot of Cucutenian Ceramic Materials of site Feteşti-La Schit (Adâncata commune, Suceava County)

In order to analyze prehistoric pottery samples, the authors used a X ray dispersal spectral analyser, EDX type 900 HS (Energy Dispersive X-ray Fluorescence (EDX) spectrometry), of high sensitivity and resolution, to highlight the chemical composition of these artefacts. In the paper are presented the results of this experimental research, performed on the batch of ceramic samples from the archaeological site Feteşti-La Schit, Suceava County. In this paper, the authors present the measurements made on some Copper Age ceramics (Cucuteni A and Cucuteni B), using Vickers hardness test to determine the hardness of different types of archaeological ceramics, as physical and mechanical indicator of these artefacts. Porosity, along with other physicochemical and mechanical characteristics, is a feature that can be used in evaluating the quality of archaeological artefacts. The authors propose a number of high techniques for the analysis of this characteristic and present the results of the digital image analysis using specialized software

Optical Properties of Composites Based on Graphene Oxide and Polystyrene

In this work, new optical properties of composites based on polystyrene (PS) microspheres and graphene oxide (GO) are reported. The radical polymerization of styrene in the presence of benzoyl peroxide, pentane and GO induces the appearance of new ester groups in the PS macromolecular chains remarked through an increase in the absorbance of the infrared (IR) band at 1743 cm−1. The decrease in the GO concentration in the PS/GO composites mass from 5 wt.% to 0.5 wt.% induces a diminution in the intensities of the D and G Raman bands of GO simultaneous with a down-shift of the D band from 1351 to 1322 cm−1. These variations correlated with the covalent functionalization of the GO layers with PS. For the first time, the photoluminescent (PL) properties of PS/GO composites are reported. The PS microspheres are characterized by a PL band at 397 nm. Through increasing the GO sheets’ concentration in the PS/GO composite mass from 0.5 wt.% to 5 wt.%, a PS PL quenching process is reported. In addition, in the presence of ultraviolet A (UVA) light, a photo-degradation process of the PS/GO composite having the GO concentration equal to 5 wt.% is demonstrated by the PL studies

Poly(Vinyl Chloride) Spheres Coated with Graphene Oxide Sheets: From Synthesis to Optical Properties and Their Applications as Flame-Retardant Agents

A new method to obtain poly(vinyl chloride) (PVC) spheres, which consists of an interaction between commercial PVC grains and hexyl ethyl cellulose and lauroyl peroxide at a temperature of 60 °C, is reported. The addition of the graphene oxide (GO) sheets dispersed in dimethylformamide to the reaction mixture leads to the generation of composites made of PVC spheres coated with GO sheets. Scanning electron microscopy studies have demonstrated that this method allows for the transformation of PVC grains with sizes between 75 and 227 μm into spheres with sizes varying from 0.7 to 3.5 μm when the GO concentration in the PVC/GO composite mass increases from 0.5 to 5 wt.%. Our studies of Raman scattering and FTIR spectroscopy highlight a series of changes that indicate the appearance of ClCH=CH–, CH2=CCl–, and/or –CH=CCl– units as a result of PVC partial dehydrogenation. New –COO– and C–OH bonds on the GO sheet surfaces are induced during the preparation of PVC spheres coated with GO sheets. A photoluminescence (PL) band with a maximum at 325 nm is reported to characterize the PVC spheres. A PVC PL quenching process is demonstrated to be induced by the increase in the concentration of the GO sheets in the PVC/GO composite mass. The perspectives regarding the use of this composite as a flame-retardant material are also reported

Absolute cross sections of the

Absolute cross sections for the 86Sr(α,n)89Zr reaction at energies close to the Gamow window are reported. Three thin SrF2 targets were irradiated using the 9 MV Tandem facility in IFIN-HH Bucharest that delivered α beams for the activation process. Two high-purity Germanium detectors were used to measure the induced activity of 89Zr in a low background environment. The experimental results are in very good agreement with Hauser-Feshbach statistical model calculations performed with the TALYS code

Absolute cross sections of the 86Sr(α,n)89Zr reaction at energies of astrophysical interest

Absolute cross sections for the 86Sr(α,n)89Zr reaction at energies close to the Gamow window are reported. Three thin SrF2 targets were irradiated using the 9 MV Tandem facility in IFIN-HH Bucharest that delivered α beams for the activation process. Two high-purity Germanium detectors were used to measure the induced activity of 89Zr in a low background environment. The experimental results are in very good agreement with Hauser-Feshbach statistical model calculations performed with the TALYS code

Some Archaeometrical Determinations on a Lot of Cucutenian Ceramic Materials of site Feteşti-La Schit (Adâncata commune, Suceava County)

Abstract: In order to analyze prehistoric pottery samples, the authors used a X ray dispersal spectral analyser, EDX type 900 HS (Energy Dispersive X-ray Fluorescence (EDX) spectrometry), of high sensitivity and resolution, to highlight the chemical composition of these artefacts. In the paper are presented the results of this experimental research, performed on the batch of ceramic samples from the archaeological site Feteşti-La Schit, Suceava County. In this paper, the authors present the measurements made on some Copper Age ceramics (Cucuteni A and Cucuteni B), using Vickers hardness test to determine the hardness of different types of archaeological ceramics, as physical and mechanical indicator of these artefacts. Porosity, along with other physicochemical and mechanical characteristics, is a feature that can be used in evaluating the quality of archaeological artefacts. The authors propose a number of high techniques for the analysis of this characteristic and present the results of the digital image analysis using specialized software

Gamma spectroscopy of even even Ytterbium isotopes.pdf

30th Symposium of the Hellenic Nuclear Physics Society (HNPS-2022), 7-8 October 2022, Ioannina, Greece</p