Zugl.: Frankfurt (Main), Universiẗat, Diss., 1986.

Zugl.: Frankfurt am Main, Univ., Diss., 2005. / Literaturverz. S. 126 - 144.

Bayreuth, Universiẗat, Diss., 2003.

No description available.

This dissertation presents the synthesis and characterization of a variety of neutral and cationic complexes featuring Group 13-15 element centres stabilized by N-, P-, and O-based donors. Unique aluminum and gallium cationic complexes are obtained from equimolar reactions of the metal halide with the chelating alkyl phosphine dmpe. However, using the analogous amine donor tmeda, neutral adducts are preferred for aluminum as well as for GaCl3, while cations are obtained for GaBr3 and GaI3. New cations of Ge(II) and Sn(II) were also discovered, featuring the coordination of either bipyridine ligands or dmpe. Utilizing bipyridine led to the expected mono and dicationic chelate complexes, however, using dmpe led to the formation of unprecedented tetracationic molecules. The reactivities of the bipyridine complexes were investigated with a variety of substrates which showcased their Lewis acidity as well as their ability to be oxidized. Finally, a new series of high oxidation-state main group cations have been synthesized using a variety of ligands. The ligand choice was found to be an important role in compound isolation as ligand degradation occurred for some of the compounds due to their high electrophilicity. Additionally, the Lewis acidity of some of the complexes leads to interesting reaction chemistry including sp3 C-H activation. Overall, the results presented herein represent new coordination chemistry for the main group elements and opens the door towards new reactivity pathways including small molecule activation and catalysis. / Graduate

The Main Zone is dominated by medium – grained, homogeneous gabbronorite, and anorthosites. The plagioclase compositions of the core is ((Na(0.227 – 0.353), K (0.012 – 0.046), Ca (0.651 – 0.777)) Al (1.630 – 1.752) Si (2.183 – 2.345) O8) and at the rim is ((Na (0.189 – 0.371), K (0.005 – 0.108), Ca (0.651 – 0.777)) Al (1.630 – 1.752) Si (2.183 – 2.345) O8). The composition of orthopyroxene is ((Mg (0.660 – 0.808), Fe (0.206 – 0.309), Ca (0.007 – 0.081)) Si (0.960 – 1.037) O3) and the compositions of clinopyroxene is ((Mg (0.229 – 0.678), Fe (0.092 – 0.427), Ca (0.012 – 0.475) Si (0.776 – 1.012) O3. The Mg# and An# varies with depth, where plagioclase increase in concentration the An# increases and the Mg# decreases. The variations in magma compositions are attributed to interlayering of different lithologies which are the result of fractional crystallisation in the magma chamber. This is supported by linear trends of the major and trace element bivariant plots. The magmatic event forming the Main Zone resulted in lateral expansion of the sheet – like magma chamber. The Main Zone formed through two magmas; first magma forming the lower Main Zone and the second magma, intruded the Main Zone at the level of the Pyroxenite Marker, forming the upper Main Zone. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

The aim of this work is to develop a preliminary design of a six-seat helicopter with a turboshaft engine. The preliminary design of the helicopter consists of processing statistical data on similar helicopters, which are then, based on the specified requirements, used to estimate the basic weight parameters of the helicopter, the main geometric parameters and to determine the type and power of the propulsion unit. It consists of calculations of basic geometric parameters of the aircraft and engine selection. Part of another solution is the aerodynamic calculation of the supporting rotor, from which both the performance of the helicopter in suspension and in forward flight flow. In a special part of the project, the attention is paid to the system of balancing the reaction torque, in this case fenestrone and the solution is supplemented by some specific means installed on the tail beam, which help to balance the reaction torque and improve the directional control parameters of the helicopter.

No description available.

No description available.

No / Improving the effectiveness of projects, particularly in construction, is of interest and concern to practitioners and academics alike. To this end, the use of partnering, now commonplace in a variety of industry sectors has been encouraged in the UK construction industry. However, in many respects project environments represent the antithesis of current thinking in partnership development and an unusual and difficult application, particularly at the lower levels in the supply chain. This paper, therefore, is concerned with evaluating the progress the UK construction industry has made in its adoption of partnering, how it is likely to develop in the future and what the implications might be for the industry¿s suppliers. The partnering experiences of Main Contractors with Main Subcontractors for structural steel products are examined and a conceptual framework of the success factors presented and discussed. Critically, clients and not suppliers were found to be major barriers to the industry¿s adoption of partnering.