[en] The level and extent of solute segregation to individual dislocations and interfaces may be visualized and quantified by atom probe tomography. The large volume of analysis and high data acquisition rate of the local electrode atom probe (LEAP) enables the solute distribution in the region of and along the core of dislocations to be estimated. Solute segregation at precipitate matrix interfaces of precipitates as small as 2 nm diameter may be quantified. Examples are presented of solute segregation to dislocations and clustering/precipitation in a neutron irradiated Fe-Ni-P model alloy and the neutron irradiated beltline weld from the Midland reactor

[en] The article “Electrosprayed catalyst layers based on graphene–carbon black hybrids for the next-generation fuel cell electrodes,” written by Lale Işıkel Şanlı, Begüm Yarar, Vildan Bayram, and Selmiye Alkan Gürsel, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on October 25, 2016, without open access.

[en] In the original article author name Qiangqiang Zhang was misspelled. It is correct here.

[en] Research on cement hydration was performed at the full-field soft transmission X-ray microscope XM-1 located at beamline 6.1.2 at the Advanced Light Source (ALS) in Berkeley CA which is operated by the Center for X-ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California. A series of works (1-3) has been conducted using this microscope for the in situ observation and qualitative analysis of through-solution hydration products and products of topochemical reactions, which form in cementitious aqueous solutions. This paper studies the precipitation of the calcium hydroxide (CH) crystals from the cement solution. The analysis of successive images of the hydration process provides critical quantitative information about the growth rate of calcium hydroxide (CH) crystals, the supersaturation ratio, and the kinetic and diffusion coefficients of the growth process. ASTM Type II portland cement and 6% C₄A₃(bar S) admixture were mixed in aqueous solution and saturated with respect to CH and gypsum. The C₄A₃(bar S) admixture was included in the experimental program because of the general research program on expansive cements, and adding C₄A₃(bar S) to portland cement is an efficient method of generating ettringite and significant early-age expansion. The solution/solid materials ratio was 10 cm³/g, which is higher than the one existing in regular concrete and mortars; to compensate for this dilution, the solution was originally saturated with CH and gypsum. To allow sufficient transmission of the soft X-rays, a small droplet was taken from the supernatant solution and assembled in the sample holder, and then squeezed between two silicon nitride windows for the analysis. The X-ray optical setup of the microscope XM-1 is described elsewhere (2). In this experiment, a wavelength of 2.4 nm (516.6 eV) was used. The radiation transmitting the sample was detected using an X-ray CCD camera, with a resolution of 35 nm provided by Fresnel zone plate X-ray optics and magnification factor of about 2000. The recorded images have a circular field of view of approximately 10 (micro)m in diameter. The illumination time per image was in the range of 1 to 14 seconds depending largely on the absorption of the sample. The experimental work was conducted at room temperature T = 298 K

[en] Heat treatments at 1300 degrees C, 1400 degrees C, 1500 degrees C, and 1600 degrees C in Ar were found to produce nanoscale precipitates in hot-pressed silicon carbide containing aluminum, boron, and carbon sintering additives (ABC-SiC). The precipitates were studied by transmission electron microscopy (TEM) and nano-probe energy-dispersive X-ray spectroscopy (nEDS). The precipitates were plate-like in shape, with a thickness, length and separation of only a few nanometers, and their size coarsened with increasing annealing temperature, accompanied by reduced number density. The distribution of the precipitates was uniform inside the SiC grains, but depleted zones were observed in the vicinity of the SiC grain boundaries. A coherent orientation relationship between the precipitates and the SiC matrix was found. Combined high-resolution electron microscopy, computer simulation, and nEDS identified an Al4C3-based structure and composition for the nano-precipitates. Most Al ions in SiC lattice exsolved as precipitates during the annealing at 1400 to 1500 degrees C. Formation mechanism and possible influences of the nanoscale precipitates on mechanical properties are discussed

[en] Yttria stabilized zirconia (YSZ) is one of the inert matrix candidates selected for investigation as host matrix for minor actinide (MA) transmutation. The structural properties of (Zr0.84, Y0.16)O1.92 beads prepared by a sol-gel method for MA infiltration, are characterized as calcined (850 C) and sintered (1,600 C) beads. The calcined YSZ beads are fine-grained and homogenous over the entire sphere and are surrounded by a uniform outer layer of approximately 30 (micro)m thickness. After sintering at 1,600 C, the beads are compacted to 51% of their initial volume and exhibit a granular structure. The thermal expansion is nearly linear for the calcined material, but shows a parabolic behavior for the sintered (1,400 C) beads. In addition, the thermal expansion of calcined material is 20-25% less than after sintering. During heating up to 1,400 C, two processes can be distinguished. The first occurs between 900 and 1,000 C and is related to an increase in unit cell order. The second process involves grain-growth of the less crystalline calcined material between 1,100 and 1,300 C. These results have implications for preparation of YSZ and its use as an inert MA transmutation matrix

[en] Due to a production error, the email address for co-corresponding author H. Fujii was omitted. The email address is fujii@jwri.osaka-u.ac.jp.

No abstract available

[en] A comparison is presented of cobalt and chromium uptake on different clays. It is shown that clay minerals are good adsorbents for cobalt and chromium in waste effluents. The sorption of cobalt and chromium on the clays studied was by ion exchange and surface complex formation, respectively. In addition, the percentage of either cobalt or chromium removed in a mixed solution environment is higher than the individual adsorption in single-component experiments. This proves a synergistic mechanism. The optimum uptake of each metal ion from mixed species was achieved by montmorillonite clay in the calcium form. (Author)

[en] Structural changes in polymethyl methacrylate (PMMA, monomer formula C₂H₂CH₃COOCH₃) induced by ⁶⁰Co radiation have been detected by means of on-line monitoring of increases in the attenuation of 10 MHz longitudinal ultrasound. Attenuation changes first became noticeable at a dose of 15 kGy and had increased by 75% at the maximum dose of 36.5 kGy. A theoretical upper bound to structural relaxation loss induced by radiation has been calculated. As a consequence it was then possible to show that at the dose levels encountered, the additional loss was attributable mainly to collective motions involving many atoms and of low attempt frequencies, rather than to the relaxation of individual atoms or structural groupings. The theory proposes an attenuation change proportional to the 5/3th power of the dose, which is in excellent agreement with experiment. It is suggested that on-line monitoring of ultrasound loss could be a sensitive diagnostic test of the onset of unwanted structural change during the practice of food preservation by the use of irradiation. (author)