Investigation of boron distribution and material migration on the W7-X divertor by picosecond LIBS

One set of horizontal target elements of the Test Divertor Units (TDU), retrieved from the Wendelstein 7-X (W7-X) vessel after the end of second divertor Operation Phase (OP1.2B) in Hydrogen (H), were investigated by picosecond Laser-Induced Breakdown Spectroscopy (ps-LIBS). The Boron (B) distribution, H pattern and the material erosion/deposition pattern on these target elements were analyzed with high depth resolution and mapped in the poloidal direction of W7-X. From the spectroscopic analysis, B, H, Carbon (C) and Molybdenum (Mo) were clearly identified. A non-uniformly distributed B pattern on these divertor target elements was determined by the combination of B layer deposition during the three boronizations and W7-X plasma operation with multiple erosion and deposition steps of B. Like the TDU, the analyzed target elements are made of fine grain graphite, but have two marker layers which allow us to determine the material migration via the ps-LIBS technique. Two net erosion zones including one main erosion zone with a peak erosion depth of 6.5 μm and one weak erosion with a peak erosion of 1.3 μm were determined. Between two net erosion zones, a net deposition zone with width of 135 mm and a thickness up to 3.5 μm at the peak deposition location was determined by the ps-LIBS technique. The B distributions are correlated with the erosion/deposition pattern and the operational time in standard magnetic configuration of W7-X in the phases after the boronizations. The thickness of the containing B layer on these target elements also correlates with the erosion/deposition depth, in which the thickness of the containing B layer varies spatially in poloidal direction between 0.1 μm and 6 μm. Complementary, Focused Ion Beam combined with Scanning Electron Microscopy (FIB-SEM) was employed also to verify and investigate the deposition layer thicknesses at typical net erosion and net deposition zones as well as to identify the three boronizations in depth.

Study of Wax Deposition Pattern of High Wax-Bearing Crude Oil Based on Cold Finger Experiment

In order to solve the problem of wax deposition in waxy crude oil from the Daqing oilfield, cold fingers were used in the experimentation. Compared with other methods, the cold finger method is simple, easy to operate, and takes little space. Measurements of wax deposition with temperature, temperature differences between the crude oil and the wall, deposition time, and cold finger rotation rate were made. The results showed that the deposition rate is up to 0.35 g/h at 8–24 h. The maximum deposition rate at 90 rotations/min was 0.26 g/h, which is 3% higher than the minimum deposition rate.

Phenomenon of primary and secondary animals within Iron Age deposits.

Animals are an integral part of deposition practices during the Danish Iron Age, and they probably represent the most common form of deposit within southern Scandinavia. Recently Gotfredsen published a volume on animals within Danish Iron Age grave contexts, but similarly comprehensive studies of animals from other contexts have not been attempted. Thus, classic sites such as Valmose, Bukkerup Langmose, and Sorte Muld still stand as the type sites for Danish Iron Age animal deposits. This article will demonstrate that there are good reasons for exploring deposits in more detail and investigate the significant variation in the treatment and quantities of sacrificial animal deposits. Furthermore, the current study has revealed a deposition pattern where a primary animal is often in the company of one or more secondary animals, the latter typically represented by a few bones. Salpetermosen Syd (MNS50010), south of Hillerød in North Zealand, Denmark is the main case study, but comparisons are made to several sites across Denmark where a similar deposition pattern has been observed.

Histotype-Dependent Oligodendroglial PrP Pathology in Sporadic CJD: A Frequent Feature of the M2C “Strain”

In sporadic Creutzfeldt-Jakob disease, molecular subtypes are neuropathologically well identified by the lesioning profile and the immunohistochemical PrPd deposition pattern in the grey matter (histotypes). While astrocytic PrP pathology has been reported in variant CJD and some less frequent histotypes (e.g., MV2K), oligodendroglial pathology has been rarely addressed. We assessed a series of sCJD cases with the aim to identify particular histotypes that could be more prone to harbor oligodendroglial PrPd. Particularly, the MM2C phenotype, in both its more “pure” and its mixed MM1+2C or MV2K+2C forms, showed more frequent oligodendroglial PrP pathology in the underlying white matter than the more common MM1/MV1 and VV2 histotypes, and was more abundant in patients with a longer disease duration. We concluded that the MM2C strain was particularly prone to accumulate PrPd in white matter oligodendrocytes.