Simple Hydroxamic acids (XHAs) are salt free, organic compounds with affinities for hard cations such as Fe3+, Np4+, Pu4+ and have been identified as suitable reagents for the control of Pu and Np in advanced nuclear fuel reprocessing. Building upon previous work on the neptunium(IV)-formohydroxamic(FHA) acid system [1], a model that describes the hydrolysis of the acetohydroxamate moiety has been extended to include hydrolysis of bishydroxamatoneptunium(IV) complex. The model has been used to determine the rate constants for hydrolysis of mono- and bis-acetohydroxamatoneptunium(IV) at 25 °C, which were found to be 1.0×10-5 dm3 mol-1 s-1 and 5.0×10-5 dm3 mol-1 s-1, respectively.

In accordance with the Belgian “supercontainer design”, spent nuclear fuel (SNF) will be encapsulated in carbon steel canisters, surrounded by a concrete overpack for disposal in poorly-indurated clay. After re-saturation of the barriers by porewater, interactions with the concrete will result in solutions rich in NaOH, KOH and Ca(OH)2. Corrosion studies of SNF in ECW-type solution (Evolved Cement Water) and YCWCa-type solution (Young Cement Water with Ca) were performed under externally applied H2 overpressures over 426 days. Directly after H2 application, Tc concentrations decreased from >10-8 M to concentrations below detection limit. Based on the fractional release of selected fission products, low matrix dissolution rates of ~10-8/day were found in both experiments. U concentrations decreased finally to 1.5•10-9 M (YCWCa) and to 2.1•10-10 M (ECW), respectively. Am, Np and Pu concentrations were found throughout the experiments below their detection limits indicating an effective retention process.

Over the past decade, the PV industry has witnessed tremendous growth in manufacturing scale and technology advancement, with PV generated electricity cost ever approaching grid parity. Among them, Si based thin film technology has made substantial progress in demonstrating its inherent advantages in lower material cost, ease of manufacturing and higher energy yield, etc. More recently, reduced product prices and competing technologies from crystalline silicon and other thin film technologies have made amorphous and microcrystalline silicon based thin film technology very challenging, and requires further increase in module efficiency and decrease in manufacturing cost. As one of the few companies in the world with significant manufacturing capacity for tandem thin film Si PV products, Chint Solar (Astronergy) has been at the forefront of technology development for the mass production of large-scale (Gen. 5, 1.43m2) Si thin film solar modules in the last 5 years. We will review major technology advancements which have been mass production proven and led to the mass produced tandem silicon thin film module with 10.0% plus stabilized efficiency, along with the field performance of those modules.

The Finnish spent nuclear fuel disposal is based on the Swedish KBS-3 concept in crystalline bedrock. The concept aims at long-term isolation and containment of spent fuel in copper canisters surrounded by bentonite buffer which mostly consists of montmorillonite. For the long-term modelling of the chemical processes in the buffer, the cation-exchange selectivity coefficients have to be known at different temperatures. In this work, the cation-exchange selectivity coefficients and cation-exchange isotherms were determined in batch experiments for montmorillonite at three different temperatures (25 °C, 50 °C and 75 °C). Five different ratios of NaClO4/Ca(ClO4)2 were used in the experimental solutions. After equilibration the solution and montmorillonite were separated and the solution analysed to get the desired exchange parameters. The experiments were modelled with a computational model capable of taking into account the physicochemical processes that take place in the experiment.

A carbonate form of Mg-Al-hydrotalcite and its p-aminobenzoate (pAB) modified derivative (i.e.,Mg(2)Al-pAB) were synthesized and characterized by means of XRD and FT-IR. The anticorrosion behavior was evaluated based on open circuit potential (OCP) of carbon steel in simulated concrete pore solution and chloride-exchange experiments. The preliminary results shown in this study demonstrated that ion-exchange indeed occurred between chlorides and the intercalated pAB anions in Mg(2)Al-pAB structure, thereby reducing the free chloride concentration in simulated concrete pore solution. The simultaneously released inhibitive pAB anions were found to exhibit the envisaged inhibiting effect and caused corrosion initiation of the steel shifting to a higher chloride concentration than without the modified hydrotalcites.

We have modified the model of rotational relaxation of stresses at mismatched interface by taking into account elastic strains of the growing film. This extended the model validity range to a wider class of compounds including pnictides. The model describes formation of low angle boundaries consisting of threading edge dislocations. Calculated interface energy shows that rotational relaxation occurs due to finite size of clusters and to non-equilibrium effect of the film growth. Subgrain size and expected angle of domain rotation depending on the lattice mismatch have been estimated. Unusual effect of increasing angle between the film subgrains at reduction of the deposition rate is predicted. The computed parameters of subgrains are consistent with the observed film nanostructure.

Intermetallic TiAl alloys are of interest to the aero engine industry because of their light weight, corrosion resistance and excellent high temperature strength. This justifies the continued effort to improve properties and processing of these alloys.

A critical parameter that limits the practical implementation of Ti aluminides is their low ductility at room temperature. Recently, a new class of TiAl alloys based on a modulated lath structure has been introduced that exhibit an excellent combination of ductility and strength. A key component in this alloy is the orthorhombic phase B19 that is attributed to alloying with high amounts of niobium. The driving forces and mechanisms that lead to the observed modulated structures involving the B19 phase are not fully understood yet. As a first step to a better understanding we present a study of the thermal stability range of the phases involved.

Elemental bismuth nanoparticles and nanotubes were obtained via microwave hydrothermal synthesis starting from bismuth oxide (Bi2O3) in the range of temperatures 200-220oC for 10-45 min. The formed nanostructures were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Relationship between reaction parameters and shape of the formed nanostructures is discussed.

We have studied the thermal conductivity of graphene using Callaway’s effective relax-ation time theory and by employing analytical expressions for phonon dispersion relations and vibrational density of states based on the semicontinuum model by Nihira and Iwata. It is found that consideration of the momentum conserving nature of three-phonon Normal pro-cesses is very important for explaining the magnitude as well as the temperature dependence of the experimentally measured results. At room temperature, the N-drift contribution (the correction term in Callaway’s theory) provides 94% addition to the result obtained from the single-mode relaxation time theory, clearly suggesting that the single-mode relaxation time approach is inadequate for describing the phonon conductivity of graphene.

Natural samples of soil, sediment and natural water were collected in the “Parc National du Mercantour” in France. Soil and sediment samples were studied to better understand the behaviors of radionuclides (RNs) in different natural compartments. Considering 137 Cs and 241 Am activities in depth (measured by α- and γ-spectrometries), two types of sediment profiles can be distinguished depending on the origin (Chernobyl accident or atmospheric nuclear weapon tests). Due to difficulties in modeling the dispersion of those RNs in natural samples, even in a protected area, semi-synthetic studies were conducted. Eu(III) was used as an analogue of Am(III). Eu behavior in water was studied by EXAFS and compared to speciation diagrams drawn in similar chemical conditions. Eu is mainly complexed by carbonate and phosphate ions. The mean Eu-O distance (2.46 Å) obtained by EXAFS is in agreement with predominant solid species determined by speciation diagrams and previous published studies.

We reported a mammalian cell-imaging paradigm to study the cellular response to single-walled carbon nanotubes (SWCNTs). Chinese Hamster Ovarian (CHO) cells were exposed to SWCNTs resuspended in physiologically compatible buffer (phosphate buffered saline, PBS), at concentrations ranging from 0 to 50 μg/mL. Upon exposure, we optically imaged the cells in order to (1) visualize the accumulation SWCNTs in cells in real-time; (2) qualitatively and quantitatively assess the morphological changes associated with cellular stress in the presence of SWCNTs; and (3) serially quantify cell survival with highly sensitive bioluminescence-based imaging. Our results showed that the cell survival obtained from optical imaging agreed with that from CellTiter-Glo (CTG) luminescence viability assay. Acute compromise in the CHO cell’s survival rate was observed under high concentrations of SWCNT exposure. The cellular response as a function of SWCNT concentrations, and exposure time was further investigated.

Osteoarthritis is a very complex illness of the joints that affects cartilage and subcondral bone. At the last years, researching has been focused in the development and characterization of composite materials, evaluating their structural properties. Some o those composite materials are constituted by organic and inorganic compounds forming hybrids. These materials can improve their properties due to the interaction of reinforcement hard particles in the polymeric matrix. The interest on the composite biomaterials has been increased on the biomedical applications such as tissue regenerating based in synthetic polymers with biodegradable and biocompatible properties whose can be reinforced by calcium phosphates. In this sense, hydroxyapatite [Ca10(PO4)6(OH)2] is often used for biological implants due its mineral phase similitude with bone microstructure and tissue compatibility. Similarly, polylactic acid (PLA) is a used polymer for implant applications due physicochemical and biocompatibility properties, and short degradation time also. In order to obtain a composite that can be used as a regenerating material on the osteoarthritis problem, in this work a (90/10 wt.%) polylactic/hydroxyapatite hybrid composite was produced by chemical synthesis and characterized by X-ray diffraction, SEM, FT-IR and TGA/DSC techniques.

There are plentiful of oolitic iron ore resources on the earth, which cannot be currently exploited because of great difficulties for beneficiating the ore. In this work, the selective fragmentation of a Chinese oolitic iron ore (which fragments ore particles along the interfaces of iron and gangue minerals) through microwave was studied in order to liberate the iron minerals at a coarse particle size and thus to effectively concentrate the iron minerals from the ore. The experimental results have shown that a large amount of fractures on the oolitic iron ore were formed along iron and gangue mineral interfaces after being treated by microwave radiation at an appropriate frequency and potential. Following a microwave treatment, the oolitic iron ore was ground by using a ball vertimill. It was indicated that the pretreatment increased the liberation of the iron and gangue minerals at the same particle size, about 10-20% and 10-30% respectively.

We apply infrared spectroscopic ellipsometry (IRSE) in combination with near-infrared to vacuum-ultraviolet ellipsometry to study the concentration and mobility of holes in a set of Mg-doped In-polar InN samples of different Mg-concentrations. P-type behavior is found in the IRSE spectra for Mg-concentrations between 1x1018 cm-3 and 3x1019 cm-3. The free-charge carrier parameters are determined using a parameterized model that accounts for phonon-plasmon coupling. From the NIR-VUV data information about layer thicknesses, surface roughness, and structural InN layer properties are extracted and related to the IRSE results.

In this work, we calculated the ground and first excited states of an electron confined in an asymmetric double DDQW system within a Gallium Arsenide (GaAs) matrix. The two-dimensional impurities density (N2d) considered in our calculation are within the range of 1012 to 1013 cm−2. We obtain the linear and nonlinear optical properties related to intersubband transitions as a function of the spacing between δ-doped wells, two-dimensional impurities concentrations as well as in presence of electric field. We reported results for the linear and nonlinear optical absorption coefficient and in the relative refractive index changes. Our results show that the asymmetry induced in the double δ-doped well system gives rise to values that are several orders of magnitude higher in the resonant peaks intensity.

A transmission electron microscopy (TEM) study on defects in a 30 μm-thick epitaxial CZT film deposited on (001)GaAs via close-spaced sublimation was performed. The epi-layer is of good quality without twins. Dislocations and stacking faults are mainly gathered near the interface. The dislocations are extrinsic either of Lomer edge or 60° type. Pseudo extrinsic stacking faults consisting of two independent and oppositely oriented extrinsic dislocations have been found both on the (111) and the planes. L-shaped defects originated from the interface have been discovered. The near-interface-side of L is consisted of 3 compressed (111) planes and the lateral side is consisted of 3-4 misarranged planes. This L-shaped defect is induced by the absence of a misfit dislocation at the intersection between L and the interface.

A series of uranium-containing gadolinium zirconate samples have been fabricated at 1723 K in air. X-ray diffraction and Raman spectroscopy have confirmed pyrochlore or defect fluorite structures, while diffuse reflectance, X-ray absorption near edge structure and X-ray photoelectron spectroscopies indicate a predominantly U6+ oxidation state, even when Ca2+ was added to charge balance for U4+. The results demonstrate the potential of gadolinium zirconates as host materials for actinides.