When a plasma is sustained in the open air, nitrogen will diffuse into the plasma. Especially for plasmas sustained by the 'Torche à Injection Axiale' (TIA) this appears to be the case, since this turbulent jet draws gases from the surroundings. In the argon plasma the entrained nitrogen is probably converted into N + 2 (via charge transfer with argon ions), which is consequently destroyed by dissociative recombination (DR). This mechanism affects the plasma in two ways: (1) it offers an important loss channel for the free electrons and (2) the gas is heated by the kinetic energy of the nitrogen atoms produced in the DR reaction.

Water tunnels built for hydropower passing through weak and heterogeneous rock mass pose challenges associated to slaking and disintegration, as they are first exposed to dry condition during excavation and are then filled with water to produce hydropower energy. Over the period of operational life, these tunnels are drained periodically for inspections and repair leading to drainage and filling cycles. The weakening of rock mass caused by cycles of drying, saturation and drainage may lead to the propagation of instabilities in the tunnels. Therefore, it is important to study the slaking and disintegration behavior of the weak rock mass consisting of clay and clay-like minerals. This paper assesses the mineralogical composition of flysch and serpentinite from the headrace tunnel of Moglicë Hydropower Project in Albania. Further, to determine the slaking and disintegration behavior of these rocks, extensive testing using both the ISRM, Int J Rock Mech Min Sci Geomech Abstr 16 (2): 143-151, (1979) suggested test method and a modified variant of this test are performed. Finally, comprehensive assessments, discussions and comparisons are made. It is found that the modified slake durability test better suits for the tunnels built as water conveying systems such as hydropower tunnels.

Strain in and around pyramidal InAs/GaAs quantum dots ͑QD's͒ fabricated by molecular-beam-epitaxy influences the density of states of the confined charge carriers. The presence of strain in QD's is required to explain their optical properties. In this paper MeV ion-channeling experiments are presented which provide evidence for the presence of strain in and around InAs QD's in GaAs. The small dimensions of the QD's ͑typical height 4 nm͒ and the presence of a wetting layer complicate the interpretation of channeling measurements, but our experiments show that extended strain fields around the QD's induce ion steering which accounts for the observed channeling behavior.

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Weak and weathered rocks are well known for their sensitivity to changes in moisture content. Degrading behavior is common in weak rocks with moisture-sensitive mineral components and present numerous stability problems. The slake durability is a measure of the resistance to weakening and disintegration of rock materials which quantitatively distinguishes durable from non-durable rock materials. Several rock material parameters interact on the process of disintegration when exposed to cyclic moisture changes, whereby the content of clay is believed to play a major role. This manuscript evaluates the overall material composition of flysch and serpentinite rocks cored from the wall of the shotcrete-lined headrace tunnel of a hydropower project, including minerals, structure, porosity, the presence of micro-discontinuities, and swelling potential, and links these properties to the slake durability. Further, the different methods used to assess compositional features affecting the durability of weak rocks are evaluated and discussed. The manuscript argues that the mineralogical composition and microstructures present in the intact rock and the content of moisture-sensitive constituents, as swelling clays, control the long-term durability of weak rock material. It is demonstrated that XRD assessments are not sufficient to detect the content of brucite and swelling components, and that methods as thin section and SEM analyses should be carried out in the assessment of weak and weathered rock mass.

The swelling potential of weak rocks is crucial to assess in stability determinations of tunnels constructed for both infrastructure and hydropower. Among the institutions that are involved with extensive research on swelling rock material, the methodologies applied at three different European institutions are reviewed in this manuscript. XRD analysis and oedometer swelling tests are included as index tests at all three institutions whereby the adopted swelling test methodologies at all three institutions are grounded in the ISRM standards. Different mindsets in how to forecast the challenges related to swelling are, however, reflected in the boundary conditions of test procedures and the internal modifications on the test apparatus, the preparation procedure, and in the choice of specimen size/mass. This manuscript reviews the adopted methodologies and highlights the advantages and drawbacks on the testing approaches used. Two of the institutions rely on a general approach which is standardized, and the results are compared. It is highlighted that, both institutions have modified the ISRM standard and the methodologies represents two unique approaches. Institution 3 have a case-specific approach and no test data were available. However, the described methodology differs from the procedures at Institution 1 and 2. Important differences between the testing procedures are both discussed and exemplified by comparing the test results obtained from duplicate samples at two of the institutions.

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