Salting constant measurements have been made on 1-naphthol, 2-naphthol, and 1-NO-2-naphthol using a distribution method at 298 K. In general, the order of the salting effect is similar to that for other acidic nonelectrolytes. However, a net salting-in is observed in the pair 1-NO-2-naphthol – NaF, and such an effect is interpreted by postulating hydrogen bonding. A comparison of results with those found for benzene, naphthalene, phenol, etc …, reveals that salt effects for organic nonelectrolytes depend upon the solute size for a given salt.Experimental ks are compared with those calculated using various salting theories. The agreement is not quantitative.

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Zirconium alloys are used as nuclear fuel cladding material due to their mechanical and corrosion resistant properties together with their favorable cross-section for neutron scattering. At running conditions, however, there will be an increase of hydrogen in the vicinity of the cladding surface at the water side of the fuel. The hydrogen will diffuse into the cladding material and at certain conditions, such as lower temperatures and external load, hydrides will precipitate out in the material and cause well known embrittlement, blistering and other unwanted effects. Using phase-field methods it is now possible to model precipitation build-up in metals, for example as a function of hydrogen concentration, temperature and external load, but the technique relies on input of parameters, such as the formation energy of the hydrides and matrix. To that end, we have computed, using the density functional theory (DFT) code GPAW, the latent heat of fusion as well as solved the crystal structure for three zirconium hydride polymorphs: δ-ZrH 1.6 , γ-ZrH, and -ZrH 2 .

Zirconium alloys are used as nuclear fuel cladding material due to their mechanical and corrosion resistant properties together with their favorable cross-section for neutron scattering. At running conditions, however, there will be an increase of hydrogen in the vicinity of the cladding surface at the water side of the fuel. The hydrogen will diffuse into the cladding material and at certain conditions, such as lower temperatures and external load, hydrides will precipitate out in the material and cause well known embrittlement, blistering and other unwanted effects. Using phase-field methods it is now possible to model precipitation build-up in metals, for example as a function of hydrogen concentration, temperature and external load, but the technique relies on input of parameters, such as the formation energy of the hydrides and matrix. To that end, we have computed, using the density functional theory (DFT) code GPAW, the latent heat of fusion as well as solved the crystal structure for three zirconium hydride polymorphs: δ-ZrH 1.6 , γ-ZrH, and -ZrH 2 .

In order to characterize the influence of hydrogen on the mechanical properties of B-titanium alloys, monotonic tensile and straincontrolled fatigue tests were performed on samples of the metastable alloy Ti-3A1-8V-6Cr-4Mo-4Zr in uncharged (0.5 at.% hydrogen) and hydrogen-charged (3-4 at.% hydrogen) conditions. The hydrogen was introduced into the material during the last 8 h of an ageing treatment (28 h at 482°C) from the gas phase, whereas the reference (uncharged) specimens were annealed completely in vacuum. The results of the mechanical tests indicate that hydrogen slightly increases the strength of the alloy in monotonic as well as in cyclic loading. Under tensile loading the fracture strain decreases as a result of hydrogen. Under cyclic loading both charged and uncharged conditions show initial softening followed by a saturation state. The cyclic lifetime at a constant total strain amplitude, however, is not reduced by the hydrogen charging. The effect of hydrogen on the mechanical behaviour can be interpreted and understood on the basis of microstructural observations that reveal a hydrogeninduced change in the precipitation state. This indirect influence of hydrogen on the microstructure, which leads to a reduction of the mean size of the a-precipitates, in combination with a slight decrease on the volume fraction of the a-phase, seems to dominate over any direct intrinsic hydrogen effect, NOMENCLATURE C, = atomic hydrogen concentration E = Young's modulus E, = Young's modulus at zero stress k = elastic constant of the quadratic extension of Hooke's law N = number of cycles Np = number of cycles to fracture A E /~ = total strain amplitude Aa/2 =stress amplitude E = total strain E* =elastic strain E, , , =plastic strain a = stress

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