Stiff macromolecules with flexible side chains are investigated by proton spin diffusion experiments with 13C detection and by a recently developed wideline separation 2D lH-13C NMR experiment (WISE-NMR spectroscopy). The conformational order and the molecular mobility of the alkyl side chains (CieHsa) are characterized for samples with polyester, polyamide, and polyimide main chains. The side chains, which are phase-separated from the main chain in a layer-type structure, can form crystalline as well as amorphous phases. The sizes of these domains depend on the nature of the main chains and their organization.In the polyimide and the polyester with regular main-chain packing, crystalline as well as amorphous regions are observed extending over more than one layer spacing. The heterogeneity observed in the polyamide is only of the order of the layer spacing. The polyester can also be obtained in a modification with uniformly ordered but anisotropically mobile side chains and conformationally disordered main chains. These results indicate coupling between the main-chain and side-chain packing in the investigated stiff macromolecules with flexible side chains.

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Coal is the most widely available fossil fuel energy resource. This work was carried out to compare the composition, Sulphur content and combustibility of the Nigerian and Nigerien coal samples. Coal samples were obtained from Enugu, Nigeria, Tahuoa and Agadez of Niger Republic. Results indicated that, coal samples from Tahuoa (RS/T) and coal from Agadez (RS/A) have highest percentage of fixed carbon (71.2% and 61.0% for Tohoua and Agadez respectively), while the coal from Enugu (RS/E), Nigeria, have the least percentage (49.2%) which made them to have high fuel ratio enabling them to be more combustible, as determined by the thermal efficiency test. The study revealed that the coal from Niger is of higher grade with ease of combustion and less smoke as found in the combustibility test. Keywords: Coal, Sulphur, fuel ratio, carbon content, combustion and thermal efficiency.

With the development of advanced engine technologies, which includes direct injected, turbo-charged, variable valve timed, flex-fuel, hybrid start-stop cycles and a general downsizing of engine architectures, bearing surface areas have decreased and connecting rod loading has increased. As a result, modern bearings experience decreased oil film thickness, more frequent non-hydrodynamic lubrication periods and higher surface sliding speeds. Subsequently, bearing applications demand an increase in fatigue and scuffing resistance. In response to this, two new complementary material developments are documented: one a new aluminum based lining material, the other a polymeric surface layer. The new lining material, called A-650, was developed to have improved fatigue strength relative to existing Al engine bearing lining options. Results for rig testing of fatigue and seizure resistance properties are provided, along with engine test evaluations using multiple fuels. The polymeric surface layer, a polyamideimide based resin called IROX™, is intended as a durable surface coating providing exceptional wear and seizure resistance under high sliding speed and start-stop conditions. Furthermore, an increase of the specific load capacity is achieved with aluminum based substrates. A description of the material, with test results, is included.

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