Tomographic KT-1 signature of phase-fraction distributions in multiphase bubble columns

Characterization of multiphase bubble column flow conditions is performed via the KT-1 signature route of computerized tomography (CT). Cross-sectional images of the bubble column are used for this study. These images were obtained non-invasively by the dual energy X-ray CT developed at Leibniz University Hannover. The solid phase is polyvinyl chloride (PVC) granules, the liquid phase is water and the gaseous phase is air. A convolution back-projection algorithm is used for tomographic reconstruction. Quantification of CT images (obtained for various combinations of liquid velocity, gas velocity and solid concentration of bubble column) is performed using CT fundamentals. The use of KT-1 as a tool for further analysis (of physical phenomenon from CT images) is demonstrated giving a very good insight into bubble column physics.     

An Improved Method for Ray Tracing Through Curved Inhomogeneities in Composite Materials

Ultrasonic NDE of anisotropic materials, due to its inherent complexity, demands a stringent approach to determine wave propagation path in presence of inhomogeneities. In addition to developing inspection procedures, the ray path information needs to be integrated with the tomographic reconstruction algorithm of composite materials. The present study proposes a method to identify inhomogeneity boundaries using edge detection approach and to implement the same in two-dimensional ray tracing model. In general, inhomogeneity boundaries can be detected on the basis of first-order gradient of a field value (such as Young's modulus). The boundaries can be represented in terms of location and orientation. This information is included in the algorithm for more accurate ray tracing. Examples show the usefulness of the method to take into effect poor penetration of ultrasound energy in certain regions of inhomogeneous materials.     

Asymmetric hydrogenation of methyl pyruvate using platinum carbonyl cluster supported on an anion exchanger as the catalyst

Anionic platinum carbonyl clusters supported on quaternary amine functionalized cross-linked polystyrene, i.e., anion exchangers, are effective precatalysts for the hydrogenation of methyl pyruvate to methyl lactate. Kinetic data has been obtained for anion exchangers with different quaternary groups. Highest observed rate constant and enantioselectivity are obtained with cinchonine funtionalized resin. The kinetic data also indicates saturation kinetics. The decarbonylated used catalyst could be recarbonylated to give a material spectroscopically (infrared) equivalent to freshly anchored cluster.     

Salvage autologous or allogeneic transplantation for multiple myeloma refractory to or relapsing after a first-line autograft?

The authors examined the effects of cognitive function, as assessed by the Mini-Mental State Examination, and drug use on the incidence of hip fracture in a community-based Swedish population of 1,608 subjects who were aged > or = 75 years on October 1, 1987, and who had not had a hip fracture. During the 7,123.8 person-year follow-up, 134 first hip fractures were identified. The Cox proportional hazards model was used to estimate the relative risk of developing hip fracture, taking into account several potential confounders. Compared with those without cognitive impairment, subjects with mild impairment (Mini-Mental State Examination scores 18-23) had a relative risk of 2.04 (95% confidence interval (CI) 1.29-3.24), and subjects with moderate-severe impairment (Mini-Mental State Examination score < 18) had a relative risk of 2.09 (95% CI 1.17-3.72). Subjects using opioid analgesics (97% took propoxyphene) had a relative risk of 2.01 (95% CI 1.19-3.40). Taking potassium supplements (99% took potassium chloride) was related to a reduced risk of hip fracture (relative risk = 0.55, 95% CI 0.31-0.98), while diuretics did not have an independent impact. In summary, the results show that cognitive impairment and use of propoxyphene are associated with increased risk of hip fracture. The observed protection of potassium chloride merits further attention. The limitation of the study was that the assessment of drug use was made only at baseline.