Pre-storage drying-transfer operations and early stage storage expose cladding to higher temperatures and much higher pressure-induced tensile hoop stresses relative to normal operation in-reactor and pool storage under these conditions. Radial hydrides precipitate during cooling and could provide an additional embrittlement mechanism as the cladding temperature decreases below the ductile-to-brittle transition temperature. To simulate this behavior, unirradiated Zircaloy-4 samples were hydrided by a gas charging method to levels that encompass the range of hydrogen concentrations observed in current used fuel. Mechanical testing was carried out by the ring compression test (RCT) method at various temperatures to evaluate the sample’s ductility for both as-hydrided and post-hydride reorientation treated specimens. As-hydrided samples with higher hydrogen concentration (>800 ppm) resulted in lower strain before fracture and reduced maximum load. Increasing RCT temperatures resulted in increased ductility of the as-hydrided cladding. A systematic radial hydride treatment was conducted at various pressures and temperatures for the hydrided samples with H content around 200 ppm. Following the radial hydride treatment, RCTs on the hydride reoriented samples were conducted and exhibited lower ductility compared to as-hydrided samples.

Ethosomes which are phospholipid vesicular systems embodying ethanol in relatively high concentrations have ever been discovered for enhanced skin delivery of drugs. The development of competent ethosome-like catanionic vesicles for dermal drug delivery is demonstrated in this work. Double-chained ion-pair-amphiphiles (IPAs or catanionic surfactants) were prepared from single-chained cationic and anionic surfactants by the precipitation method. These lipid-like surfactants were thereafter used as the material to prepare the catanionic vesicles with the aid of ethanol as the cosolvent in aqueous buffer solution by a simple semispontaneous process. Formability and physical stability of the as-prepared ethosome-like catanionic vesicles were discussed based on the viewpoint of mixed solvent dielectric constant. The potential application of the ethosome-like catanionic vesicles as nano-carriers in dermal drug delivery was illustrated by the encapsulation of hydrophobic and hydrophilic drugs. Furthermore, effects of ethanol and cholesterol addition on physical stability, bilayer membrane rigidity, encapsulation efficiency, and release rate of the ethosome-like catanionic vesicles were systematically studied. The performance of ethosome-like catanionic vesicles as drug delivery nano-carriers, eventually, can be tailored by the concentrations of ethanol and. cholesterol. The results of gelation of drugs loaded ethosome-like catanionic vesicles by water soluble polymers with and without hydrophobical modifications, as revealed by the phase maps and the rheological properties, then provide useful information for practical use of the ethosome-like catanionic vesicles in dermal delivery of drugs.

New multiple layered perovskites with general formula RbLaNaxNb2+xO7+3x, x = 1 and 2, were synthesized via a ceramic method. While the triple layered compound could be obtained by simple direct reaction, the quadruple layered one was synthesized using a two-step solid state approach. The compounds were characterized by X-ray powder diffraction; the newly obtained compounds appear to be isostructural with the previously reported RbCa2Nb3O10 and RbCa2NaNb4O13 for RbLaNaNb3O10 and RbLaNa2Nb4O13, respectively. Preliminary results show that the new compounds can undergo ion exchange reactions involving alkali metals and transition metal chlorides.

The main objective of this study was to develop a polymeric drug delivery system for tamoxifen (TMX), intended to be injectable Eudragit® nanoparticles (NP) for breast cancer treatment. TMX-Eudragit-NP were characterized in terms of particle size, surface morphology, drug physical state by using photon correlation spectrometry (PCS), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The entrapment efficiency (%EE) and in vitro drug release studies were estimated spectrophotometrically by UV-vis technique. The cell toxicity assay was performed in 4T1 cell line using MTT test. TMX-Eudragit-NP showed a maximum entrapment efficient of 23%. The size measurements were compared with the empty nanoparticles and showed values of TMX-Eudragit-NP = 133 ± 30 nm nm, and empty- NP = 273± 50 nm. The zeta potential of particles was +65 and +38 mV for TMX-Eudragit-NP and empty-NP respectively. FTIR studies did not indicate changes in chemical structure or polymer-drug interaction. The cytotoxicity against the 4T1 cells was affected significantly by the released amount of TMX, while empty-NP exhibit no significant cytotoxicity against mouse breast cancer cells (4T1 cell line).

We present rational computational design of phenothiazine dyes for dye-sensitized solar cells containing different five-membered rings (thiophene, furan, and selenophene) by a combined strategy of modified conjugation order and functionalization leading to the quinoidization of the ring. We predict that it is possible to lower the excitation energy by 20% vs. the parent dye by the combination of: change in the conjugation order of the methine unit, its functionalization by the CN group, and replacement of the thiophene ring by furan.

A novel type of nitrogen-doped hierarchically 3D macroporous CMG films electrode (NCMG) was prepared through a facile ultrafiltration method using graphene oxide (GO) and polystyrene (PS) as precursors, then annealed in N2 atmosphere at 1000°. This NCMG electrode exhibits high specific capacitance (150 F g-1), excellent rate capacity and good cycle life (98% of initial capacitance), which can be a good candidate for supercapacitor application.

Carbon nanotube (CNT) and graphene films form on silicon carbon (SiC) using a metal-catalyst-free thermal decomposition approach. In this work, the growth conditions used in the decomposition process are varied to investigate their impact on the type and quality of carbon allotrope formed on the SiC substrate. The nanostructure growth is performed using two approaches, both of which involve intense heating (1250-1700oC) under moderate vacuum conditions (10-2 – 10-5 Torr) without the aid of carbon rich feed gases or metal catalysts commonly used in Chemical Vapor Deposition (CVD) growth approaches. The first growth method uses a graphite resistance furnace capable of annealing wafer-sized samples. The second approach uses a high-intensity laser to heat a micro-meter scale spot size. The high-intensity laser heats the illuminated area of the SiC substrate while under vacuum conditions, resulting in a small-scale growth process similar to the conventional resistance furnace technique. Unique to this micro-scale approach is that in situ Raman spectroscopy is performed yielding instantaneous characterization of the resultant carbon nanostructure as it is formed. The laser-induced growth mechanism enables the impact of varied background vacuum pressures and temperatures to be evaluated in situ. This work reports the findings for various parameter sets implemented during growth, and provides insight into the physical mechanism influencing the growth process.

The exchange of the extra-framework Na+ ions in Engelhard titanosilicate (ETS-10) with Ag+ and Ru3+ has been investigated theoretically by means of density functional theory (DFT) and experimentally, with the aim of elucidating its effects on the structural, electronic and vibrational properties of the Ti-O-Ti quantum wire. A comparison of theoretical findings and experimental Raman data in the region of Ti-O-Ti stretching reveals that the introduction of the Ag+ ions preserves the integrity of the wire to a large extent while Ru3+ ions cause large-scale distortions along with some loss in crystallinity.

This study evaluates the behavior of the adherence layers - sawn flat iron boride formed on the surface of steels used in manufacturing industry in Mexico. In steels AISI 1018, AISI 8620 and AISI 316 was characterized this behavior, boriding thermochemical treatment with box technique, with a processing temperature of 1273 °K, with an exposure time of 8 hours. Furthermore the adherence is assessed by the Rockwell C hardness technique prescribed by the German standard VDI 3198 of traction, this impact test qualitatively determine the type of adherence formed three thermochemical steels treated by the technique of boriding. Moreover optical microscopy determines the type of film morphology FeB/ Fe2B of each of the materials exposed to a boriding, also shows the thicknesses of the phases generated in the surface type in all three steels boriding. Phase presence boride FeB/Fe2B was determined by X -ray diffraction (XRD). Technique for scanning electron microscopy (EDS) was evaluated qualitatively the presence of FeB/Fe2B of boronizing. Otherwise determines the hardness and elastic modulus by nanoindentation technique of the phases present in the three steels. Lastly, AISI 1018 and AISI 8620 are bounding scale H1 to H3, the AISI 316 steel has an adherence of H3 to H6 under German standard VDI 3198.

An overview is given of an International Atomic Energy Agency Coordinated Research Project (CRP) on the treatment of irradiated graphite (i-graphite) to meet acceptance criteria for waste disposal. Graphite is a unique radioactive waste stream, with some quarter-million metric tons worldwide eventually needing to be disposed of. The CRP has involved 24 organizations from 10 Member States. Innovative and conventional methods for i-graphite characterization, retrieval, treatment and conditioning technologies have been explored in the course of this work, and offer a range of options for competent authorities in individual Member States to deploy according to local requirements and regulatory conditions.

The highest efficiency CuIn1-xGaxSe2 (CIGS) based solar cells have been produced from films with x∼0.3 which gives a value of Eg around 1.1-1.2eV. Increasing the Ga content of the CIGS absorber provides an increase in Voc, allows tuning of the band gap that can enhance performance under actual operating conditions, and potentially makes it possible to use CIGS films in multi-junction devices. However, champion cells have not yet been produced for values of x significantly greater than 0.3. This work focuses on how increased Ga content in CIGS films affects the recombination behavior of grain boundaries. Cathodoluminescence spectral imaging (CLSI) measurements on fully processed devices allow us to compare device properties with recombination behavior and optical properties of grain boundaries in films with different Ga content. Our data suggests that grain boundaries in high efficiency films with x∼0.3 exhibit a significant red shift in the CL spectra whereas grain boundaries in films with higher Ga content typically show either a small shift or none at all. This shift indicates band bending near the boundaries which could enhance charge separation and subsequent collection of carriers generated near grain boundaries. This is investigated statistically to identify trends in different regions of the films.

In this study, an in vitro blood-brain barrier model was developed using murine brain endothelioma cells (b.End3 cells). By comparing the permeability of FITC-Dextran at increasing exposure times in serum-free medium to such values in the literature, we confirm that the blood-brain barrier model was successfully established. After such confirmation, the permeability of five ferrofluid (FF) nanoparticle samples, GGB (ferrofluid synthesized using glycine, glutamic acid and BSA), GGC (glycine, glutamic acid and collagen), GGP (glycine, glutamic acid and PVA), BPC (BSA, PEG and collagen) and CPB (collagen, PVA and BSA), was determined using this model. In addition, all the five FF samples were characterized by zeta potential to determine their charge as well as TEM and dynamic light scattering for determining their hydrodynamic diameter. Results showed that FF coated with collagen had better permeability to the blood-brain barrier than FF coated with glycine and glutamic acid based on an increase of 4.5% in permeability. Through such experiments, magnetic nanomaterials, such as ferrofluids, that are less permeable to the blood brain barrier can be used to decrease neural tissue toxicity and magnetic nanomaterials with more permeable to the blood-brain barrier can be used for brain drug delivery.

Surface-induced aromatic stabilization (SIAS), a recently proposed mechanism leading to a formation of charge-transfer (CT) states at organic/metal (O/M) interfaces [G. Heimel, et al., Nat. Chem.5, 187 (2013)], was investigated for an aromatic hydrocarbon, diindenoperylene (DIP), by means of synchrotron radiation-based ultraviolet photoelectron spectroscopy (UPS). By employing DIP and noble metal substrates (Ag and Cu), we confirmed the formation of CT states, indicating that an inclusion of a specific functional group with a hetero-atom within adsorbate molecules as suggested before is not necessarily required for the formation of CT states mediated by the SIAS. With a comparison of the mother and analogue molecules, perylene and PTCDA, we discuss the structural requirement for the realization of the SIAS.

The lower dielectric constant (k) insulator is required for faster, smaller, and higher performance integrated circuit of the microprocessor and other advanced semiconductor devices that are so important to modern electronics and information technologies. Aromatic polyimides are among the candidate materials of low k due to their high thermal stability, mechanical strength and chemical resistance.

In this work, we show an 2,6-di-tert-butyl-9,10-diphenylanthracene core based novel polyimide which has been designed to have the lower polar imide concentration compared to that of conventional polyimides as well as the synthesis and characterization of its constitutional units, diamine and dianhydride.

We analyze photoluminescence (PL) and electroluminescence (EL) using a hyperspectral imager that records spectrally resolved luminescence images of solar cell absorbers. The system is calibrated to yield the luminescence flux in absolute values. This system enables to quantitatively image physical parameters such as the photovoltage with an uncertainty of less than 30mV. The wide field illumination, low power excitation and fast acquisition brings new insights compared to classical setups such as confocal microscope. Several types of absorbers have been analyzed. For instance, we can investigate spatial fluctuations of the Quasi Fermi Levels splitting in CIGS polycristalline absorbers and link those fluctuations to transport properties. The method is general to the point that third generation PV cells absorbers can also be evaluated. We illustrate the great potential of our setup by imaging carrier temperature in Hot Carriers Solar cells absorbers and quasi Fermi levels splitting in Intermediate Band Solar cells.

The effect of strain rate on hydrogen embrittlement of low alloy 4340 steel was studied using double-notched tensile samples electrochemically charged in-situ with hydrogen in 1N H2SO4 + 5 mg/l As2O3 solution. The mechanical response of samples with prior austenitic grain sizes of 10 and 40 μm and martensitic hardness of 43-52 HRC were examined after hydrogen charging times of 0-20 min. Increasing the strain rate for hydrogen charged samples resulted in decreased failure strains and increased evidence of brittle fracture. Brittle fracture surfaces for the harder samples showed primarily intergranular fracture while softer samples exhibited predominantly quasi-cleavage.

Recently, Fickenscher et al. [1] have shown that, in a core-multi-shell structure where a GaAs quantum well is embedded into an AlGaAs shell wrapped around a [111] oriented GaAs nanowire, the electron and hole ground states are strongly confined to the corners of the hexagonally symmetric quantum well. Thus this confinement defines quantum wires which run along the length of the nanowires along its corners. Here we review single nanowire photoluminescence measurements which show the significant confinement energy of the excitons. For well widths larger than 5 nm, optical transitions between electron and hole excited states can be seen in excitation spectra, while for widths less than 5 nm only the ground state optical transitions are observed. For well widths smaller than 5 nm, high resolution spatially resolved photoluminescence measurements show directly the appearance of localized states. Single nanowire spectra from the 4 nm QWT sample display ultranarrow emission lines on the high energy side of the luminescence band. Spatially-resolved PL images show that these quantum dots are localized randomly along the length of the wire.

In this paper, high temperature (>1400°C) thermal oxidation has been applied, for the first time, to 4H-SiC PiN diodes with thick (110 μm) drift regions, for the purpose of increasing the carrier lifetime in the semiconductor. PiN diodes were fabricated using 4H-SiC material that had undergone thermal oxidation performed at 1400°C, 1500°C and 1600°C, then were electrically characterized. Forward current-voltage (I-V) measurements showed that thermally oxidized PiN diodes exhibited considerably improved electrical characteristics, with devices oxidized at 1500°C having a forward voltage drop (V F ) of 4.15 V and a differential on-resistance (R on,diff ) of 8.9 mΩ-cm2 at 100 A/cm2 and 25°C. Compared to typical control sample PiN diode characteristics, this equated to an improvement of 8% and 23% for V F and R on,diff , respectively. From analysis of the reverse recovery characteristics, the carrier lifetime of the PiN diodes oxidized at 1500°C was found to be 1.05 μs, which was an improvement of around 30% compared to the control sample PiN diodes.

We show evidence that the competition between the antiferromagnetic metallic phase and the charge- and orbital-ordered insulating phase at the reentrant phase boundary of a layered manganite, LaSr2Mn2O7, can be manipulated using ultrafast optical excitation. The time-dependent evolution of the Jahn-Teller superlattice reflection, the indicator of the formation of charge and orbital order, was measured at different laser fluences. The laser-induced change in the Jahn-Teller reflection intensity shows a reversal of sign between earlier (∼10 ns) and later (∼150 ns) times during the relaxation of the sample. This is consistent with a physics picture whereby the laser excitation modulates the local competition between the metallic and the insulating phases.