Search

This recent study investigates the properties of recycled polypropylene (RPP)/peanut shell powder (PSP) composites under the effect of electron beam (EB) irradiation. RPP/PSP composites were prepared by melt‐mixing and compression molding with 0 to 40 wt% of PSP loading. The fabricated composites were then irradiated using 2.0 MeV EB accelerator at a fixed dose of 40 kGy. The properties of nonirradiated and irradiated composites were compared and characterized by gel content, tensile properties, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and water absorption behavior. The results in tensile strength and tensile modulus of irradiated RPP/PSP composites show an increment while decrement in elongation at break. The gel content analysis result shows an increase upon irradiation indicated that the irradiation induced crosslinking between the components. The thermal stability of irradiated composites was also improved compared to nonirradiated composites. The enhanced interfacial adhesion and crosslinking between components was evidenced by SEM morphology. POLYM. COMPOS., 39:3048–3056, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The work describes the preparation and physical-mechanical characterization of unidirectional CFRP panels manufactured by an electron beam curing technique. Delamination fracture toughness in Mode I and II is investigated in order to evaluate the influence of fiber-matrix adhesion strength, matrix toughness and matrix crosslinking density as determined by the radiation curing process. A matrix system comprising a DGEBA epoxy monomer and an initiator of cationic polymerization have been used, with one batch of resin mixed with a PES monomer in order to enhance matrix toughness. Curing was achieved with a pulsed 10 MeV Electron Beam accelerator. Thermally cured composite systems have also been manufactured and tested for comparison. Results from double cantilever beam and end notched flexure delamination tests have been analyzed and correlated with results from short beam shear, dynamic mechanical thermal analysis tests and SEM micrographs of delaminated surfaces. POLYM. COMPOS., 35:1529-1542, 2014. © 2013 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

The structural, optical and morphological properties of Ga-rich GaInP layers with various gallium compositions grown on epi-ready semi-insulating (100)-oriented GaAs substrates by using Molecular Beam Epitaxy technique are presented in this study. The GaInP/GaAs structures ( S1, S2 and S3) have been evaluated by means of high resolution X-ray diffraction, photoluminescence (PL) and atomic force microscopy measurements at room temperature. Experimental forward and reverse bias current-voltage ( I- V) characteristics of structure S3 was investigated at room temperature due to its better characteristics when compared to the other two samples. The main electrical parameters such as ideality factor ( n), barrier height (Φ) and series resistance ( R) were extracted from forward bias I- V characteristics and Cheung's function. In addition, Hall measurements were carried out as a function of temperature (30-300 K) and at a magnetic field of 0.4 T were presented for structure S3. [ABSTRACT FROM AUTHOR]

Electron paramagnetic resonance (EPR) dosimetry of tooth enamel in X-band has been established as a suitable method for individual reconstruction of doses 0.1 Gy and higher. The objective was to demonstrate the feasibility of using Q-band EPR in small biopsy tooth enamel samples to provide accurate measurements of radiation doses. Q-band spectra of small (<10 mg) irradiated samples of dentine and bone were studied to investigate the possibility of using Q-band EPR for dose measurements in those materials if there are limited amounts of enamel available, and there is no time for the chemical sample preparation required for accurate X-band measurements in dental enamel. Our results have shown that Q-band provides accurate measurements of radiation doses higher than 0.5 Gy in tooth enamel biopsy samples as small as 2 mg. Q-band EPR spectra in powdered dentine and bone demonstrated significantly higher resolution and sensitivity than in conventional X-band measurements. [ABSTRACT FROM AUTHOR]

Radiation induced leakage current in a vari- able-thickness SiO&sub2;-on-Si structure (1.0-6.5 nm) is detected and characterized by a novel technique, time-dependent electric field-Induced second-harmonic generation (EFISH). The role of second-harmonic generation (S HG) for in situ monitoring of the DC field across the oxide and its utility in understanding the dynamics of the carriers in response to their photo-injection is discussed. Plausible mechanisms responsible for radiation-induced leakage current through thin oxides are used to explain the experimental results. [ABSTRACT FROM AUTHOR]

The kinetics of the outer-sphere oxidation of Cr(NN)[sub 3] [sup 2+] ions (NN = 2,2'-bipyridine, 1,10-phenanthroline, and their substituted analogs) by hexaammineruthenium(III) was studied using laser flash photolysis. The Cr(NN)[sub 3] [sup 2+] ions were generated via the reductive quenching of the *Cr(NN)[sub 3] [sup 3+] excited states by oxalate ions or by H[sub 2] edta[sup 2–] . The second-order rate constants were found to vary with the driving force of the reaction. The rate constants increase from (7.1 ± 0.5) × 10[sup 6] M[sup –1] s[sup –1] for Cr(5-Clphen)[sub 3] [sup 2+] to (2.6 ± 0.2) × 10[sup 8] M[sup –1] s[sup –1] for Cr(4,7-Me[sub 2] phen)[sub 3] [sup 2+] . The self-exchange rate constant for the couple (Cr(NN)[sub 3] [sup 3+/2+] ) was calculated by applying Marcus cross relation to present and other known reactions of Cr(NN)[sub 3] [sup n+] ions, where n = 3 or 2 with various reactants and is estimated to be (6 ± 4) × 10[sup 7] M[sup –1] s[sup –1] .Key words: tris(polypyridyl)chromium(II)/(III) self-exchange rate, hexaammineruthenium(III), oxidation of Cr(NN)[sub 3] [sup 2+] .Faisant appel à la photolyse éclair au laser, on a étudié la cinétique de l'oxydation dans la couche externe d'ions Cr(NN)[sub 3] [sup 2+] (NN = 2,2'-bipyridine, 1,10-phénanthroline et leurs analogues substitués) par l'hexaamineruthénium(III). Les ions Cr(NN)[sub 3] [sup 2+] ont été générés par le biais d'un piégeage réducteur des états excités *Cr(NN)[sub 3] [sup 3+] par des ions oxalate ou par du H[sub 2] edta[sup 2-] . On a trouvé que les constantes de vitesse du deuxième ordre varient avec l'affinité de la réaction. Les constantes de vitesse augmentent de (7,1 ± 0,5) × 10[sup 6] M[sup –1] s[sup –1] pour le Cr(5-Clphen)[sub 3] [sup 2+] à (2,6 ± 0,2) × 10[sup 8] M[sup –1] s[sup –1] pour le Cr(4,7-Me[sub 2] phen)[sub 3] [sup 2+] . On a calculé la constante de vitesse d'autoéchange du couple Cr(NN)[sub 3] [sup 3+/2+] en appliquant la relation croisée de Marcus à ces réactions et à d'autres réactions connues d'ions Cr(NN)[sub 3] [sup n+] (n = 3 ou 2) avec divers réactifs et on l'a évaluée à (6 ± 4) × 10[sup 7] M[sup –1] s[sup –1] .Mots clés : vitesse d'autoéchange tris(polypyridyl)chrome(II)/(III), hexaamineruthénium(III), oxydation de Cr(NN)[sub 3] [sup 2+] .[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the dose dependence of the radiation induced leakage current (RILC) from the linear energy transfer of the ionizing radiation. Devices and experiments; Kinetics and angular dependence of RILC and radiation induced soft breakdown; Conclusions.

Presents information on a study which developed an analytical model of Radiation Induced Leakage Current (RILC) for ultra-thin gate oxides submitted to high dose ionizing radiation. Information on RILC; Experimental details; Results and discussion; Conclusions.

In this paper we compare the spectral, acid-base, electrochemical, and kinetic properties of the excited states and one-electron reduced forms of homo- and heteroleptic Ru(II)-diimine photosensitizers that contain 2,2'-bipyridine, 2,2'-bipyrazine, and 2,2'-bipyrimidine ligands. These species, represented as *(RuIIIL.-)2+ and (RuIIL.-)+, respectively, are orbital analogues in that the intra- or intermolecularly transferred electron resides on the same uniquely reduced ligand. The variations in the properties of these species, resulting from changes in the coordinating ligands, permit the fine-tuning of photochemical systems. [ABSTRACT FROM AUTHOR]

The time recovery of the spectroscopic capabilities of CdZnTe and CdTe detectors, irradiated with increasing doses of high- and low-energy neutrons, as well as electrons, has been investigated by studying their spectroscopic behavior at different photon energies using leakage current measurements and PICTS (photo-induced current transient spectroscopy) analysis. The detectors were stored at room temperature for up to one year to study the time evolution of their spectroscopic performance and to correlate it with the presence of defective states in the material. We have observed a clear improvement in the material’s detection properties with time, though only in those detectors which have not been severely degraded by the irradiation. The recovery can be associated with a decrease in the concentration of some defective states, thus allowing the assessment of the crucial role these play in determining the charge collection processes in the material and its spectroscopic capabilities. [ABSTRACT FROM AUTHOR]

Presents information on a study which shows that carnosine increases the irradiation hindrance of Aeromonas hydrophila in minced turkey meat. What gram-negative bacterial pathogens include; Uses of antioxidants, specifically those that are naturally present in skeletal muscle in food preservation; Characteristics of carnosine.