Controlled Synthesis,Characterization, and Flow Properties of Ethylene–Diene Copolymers

The flow response of branched entangled resins is dominated by the branching topology of the constituent molecules, a property that is not directly accessible using experimental analytical tools for industrially relevant complex resins. In this paper, the controlled terpolymerization of ethylene, 1,9‐decadiene, and either hexene or octene in a continuous stirred tank reactor with a metallocene catalyst, is reported. The synthesized samples are characterized extensively with various analytical tools and their rheological properties are measured with small amplitude oscillatory shear and start‐up uniaxial extension experiments. A model is developed for the polymerization process with the mass balance during synthesis providing strong constraints on the rate constants. In silico ensembles of molecules, generated via Monte Carlo sampling, are used to reproduce the experimental results. The computer model allows us to infer the detailed branching structure of the molecules and to predict the optimum range of reactor conditions for this synthesis.     

Performance studies of energy consumption for single and multiple nozzle systems under impinging air jets

Impinging air jets of various shapes, sizes and configurations are commonly used in heating, cooling and drying industrial processes. An analytical study has been carried out to optimise the thermal performance of single and multiple nozzle systems using impinging air jets. The optimisation of the nozzle array was given for practical purposes. The results show that within practical limits, a narrower nozzle size results in a greater heat and mass transfer coefficient. An economical analysis of the drying processes is also given for slot nozzles.     

Elemental composition of hair and bone density measurements at diagnosis in paediatric inflammatory bowel disease

A dual energy X-ray absorptiometry (DEXA) system has been employed to measure the bone mineral density (BMD) of children with inflammatory bowel disease (IBD); Crohn's disease (CD) and ulcerative colitis (UC) at diagnosis. The results of the study indicate that even at diagnosis, a significantly reduced bone mineral density measured in terms of the Z-score, was observed in the lumbar spine and whole body of the IBD subjects. This was found to be more pronounced in Crohn's disease than in the ulcerative colitis subjects. Furthermore, the study was extended to investigate the elemental composition of hair of IBD subjects and age matched controls using instrumental neutron activation analysis (INAA). The concentrations of 11 elements; Al, Br, Ca, Cl, Cu, I, K, Mg, Mn, Na and V were determined. A significantly reduced concentration of Ca, Cu, K, Mn, and V were observed in the hair of IBD subjects as compared to the control group. This revised version was published online in August 2006 with corrections to the Cover Date.