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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Bulk flow properties of fine binary powder mixtures

Kojima, Takehiro January 2014 (has links)
No description available.

Flow of liquid metal through packed bed electrodes

Craig, Andrew John January 1980 (has links)
No description available.

Architecture and performance of ultra-fine scale alumina fibre membranes

Su, Veronica Mei Tiing January 2014 (has links)
No description available.

Some aspects of the relationship between loss, domain wall motion and ageing in grain oriented silicon iron

Beckley, P. January 1969 (has links)
No description available.

Surface engineering of metal oxides using polynucleating ligands

Cooper, Rachel J. January 2006 (has links)
Chapter 1 provides a general review of functionalised ligands used in surface engineering and considers applications such as corrosion protection, pigment dispersion, adhesion promotion and friction modification. The passivation of aluminium flake used in water-based metallic paints is considered in Chapter 2. Current processes for the pre-treatment of aluminium involve toxic materials and the development of benign alternatives is discussed. Measurements of adsorption isotherms by ICP-OES of a series of <i>mono</i> and <i>di</i>phosphonic acids that bind strongly to aluminium trihydroxide (ATH) are correlated with performance in passivation tests based on hydrogen evolution. Ligands allowing secondary binding interactions through additional functional groups showed higher equilibrium adsorption constants than unfunctionalised analogues but had a negative effect on the passivating ability. The most efficient passivators are those with long hydrophobic chains, e.g. octylphosphonic acid and dodecylphosphonic acid and Al-flake treated with these performed as well as commercially available passivated Al-flake. The design criteria for the formation of ternary (dye/cyclodextrin/surface) complexes for the protection of water soluble azo-dyes that are inkjet printed onto oxide treated papers is discussed in Chapter 3. 4-(4’-Hydroxyphenylazo)phenylarsonic acid, 4-(4’-aminophenylazo)phenylarsonic acid and 4-(4’dimethylaminephenylazo)benzene arsenic acid display evidence for <i>multi</i>-layering when adsorbed on goethite (Chapter 4). In Chapter 5, alternative surface treatments for metal oxides are discussed which use some of the design features assumed to be important in chromating of oxide surfaces, notably the formation of thermodynamically and kinetically stable M(III) oxo or hydroxyl complexes. The possibility of using cobalt(III) amine complexes which have some labile coordination sites was investigated.

Fatigue crack propagation in a low alloy steel under complex load sequences

Wade, E. H. R. January 1975 (has links)
No description available.

Study of the vapour pressures of ZrCl4, SnCl2 and SnBr2 by the Knudsen effusion method

Abdalla, Osama Abdelhameed January 1972 (has links)
The theoretical basis of the Knudsen effusion method for the measurement of vapour pressures is considered, and the complications inherent in real Knudsen cells and samples are discussed. The thermogravimetric effusion technique and procedure used to determine the"vapour pressures of zirconium tetrachloride with six effusion orifices of different size are described. The results show a strong dependency of measured pressure on orifice size, such that the pressure increases with decreasing orifice area. The Motzfeldt's relationship between equilibrium and steady-state pressures was employed to obtain equilibrium vaporization characteristics of ZrC14• The derived equilibrium pressures fall close to the values obtained from previous static measurements. The sublimation pressures of tin dichloride and tin dibromide were studied in an identical manner, with four and three different orifice sizes, respectively. No systematic variation of measured pressure with orifice size was noted. Self-consistent heats of Sublimation from the data for each orifice were obtained for both.dihalides. An argument is presented whereby the evident vaporization behaviour of the compounds studied can be related to their structural types.

The effect of solidification variables on the microstructure of hypereutectic Al-Si alloys

Faraji, Masoumeh January 2007 (has links)
In this work, the effect of phosphorus, as a primary silicon refiner, and of strontium, as a eutectic silicon modifier, individually and simultaneously, on the microstructure ofhypereutectic AI-Si alloys was studied. AI-18.6Si-0.35Fe-0.02Cu-0.0014P (wt%) alloy was used for casting and phosphorus was added in a range of 0.015-0.08 wt% mainly by means of AI-6.75Fe4.91P (wt %), and in a few cases by AI-17.lCu-0.89P (wt%), master alloys. Eutectic silicon was modified using AI-5.93 wt% Sr over a range of 0.04-0.3 wt% Sr. Two different casting methods were used: bottom casting into sand moulds and chamber casting into steel moulds. The melt temperature was 800aC and holding time for each addition was 15 min. Adding 0.02 wt% P led to an increase in the number of primary silicon particles per unit volume (NV) by 1.5 times. NV was trebled by adding 0.08 wt% phosphorus during chamber casting into steel moulds. NV was decreased by about 20 times by adding 0.2 wt% Sr and 0.02 wt% Sr+0.02 wt% P to untreated alloy during bottom casting into a sand mould. Adding strontium increased primary silicon undercooling from 7.l±1.0 to 46.6±6.5 K, though phosphorus addition of 0.02, 0.04 and 0.08 wt% (for ingots chamber cast into steel moulds) gave a primary silicon undercooling of 18.7±10A, 8.5±1.2 and 9.l±0.9 K respectively (compared to 9.0±5.0 K for untreated ingots). The nucleation models (one surface-dependant and the other volumedependant) of Perepezko were applied to the observed nucleation behaviour of primary silicon. It was found that the nucleation temperature was the most crucial variable in both models. Applying the models to our results showed that contact angle from the surface-dependant model varied over the range of 24.3 to 30 degrees, compared with 17.7 to 23.5 degrees from the volume-dependant model. Additionally, Electron Back Scatter Diffraction (EBSD) was used to determine possible crystallographic relationships between neighbouring primary silicons in untreated and P-inoculated ingots. Between two connected primary silicon particles, the outermost layers of each silicon particle were often found to be twin-related by a 60° rotation around axis <111>.

Excitations in strontium titanate and palladium-iron

Stirling, W. G. January 1972 (has links)
No description available.

Precipitation in iron molybdenum nitrogen alloys

Speirs, David L. January 1969 (has links)
The precipitation of nitrogen fron iron-molybdenum-nitrogen alloys has been studied by X-ray, electron microscopic and optical metallographic techniques in the temperature range 100 - 800°C. By experimental control of reaction conditions, nine different precipitated phases are characterized in alloys containing up to 5.0 wt. % molybdenum. In the temperature range 100 - 8oo°c it is shown that all known molybdenum nitrides and one of the two known ternary iron-molybdenum nitrides occur as precipitates. Previous work on the influence of oxygen on these phases is confirmed and shown to be applicable to the phases when precipitated in iron. Below about 400oC the diffusion of molybdenum is too slow to precipitate binary or ternary alloying-element nitrides and para-precipitation or iron nitrides occurs. Quench-ageing observations show that the decrease of the activity coefficient of nitrogen in iron solid solution with increase in molybdenum concentration leads to a marked retardation in the rate of precipitation at these low temperatures. Materials of exceptional hardness are obtained at 450° - 650°C by "constant nitrogen activity ageing" of alloys containing 2.0 - 5.0 wt. %Mo. It is suggested that the unique properties of these materials are due to homogeneous precipitation of molybdenum and nitrogen which goes through each of the stages well-recognised in face-centred cubic alloys, i. e. G. P. zone formation-metastable precipitate->equilibriun precipitate The occurrence of Guinier-Preston zones involving both substitutional and interstitial solute atoms is demonstrated for the first time and is thought to be of wide scientific and technological application.

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