ProfessorProfessor of paediatrics Dar es Salaam, Tanzania (b Tanzania 1936; q Makerere University, Uganda, 1964; DCH, FRCP Ed, FRCP Glas), d 29 May 2005. Figure 1 Valerian Kimati did his postgraduate training in Glasgow. Returning to Tanzania, he had a distinguished career, becoming the first Tanzanian professor of paediatrics at the University of Dar es Salaam in 1979. He was president of the Medical Association of Tanzania and the first president of the Paediatric Association of Tanzania. He later became Unicef regional adviser in primary health care for south central Asia. After retirement at 60 he embarked on another career as professor of paediatrics at the International Medical and Technological University, Dar es Salaam, where he was also appointed vice chancellor. He leaves a wife, Eugenia, and two children.
Barnes, P.; Jenkins, M.; Baldock, C.; Lutkin, J. E.; Burwod, R. J.; Jeyakumar, T. Author Information
Baldock, C.; Batchelor, S.; Barnes, P.; Lutkin, J. E.; Patval, S.; Burwood, R. J. Author Information
Nuclear Medicine Department, Royal Sussex County Hospital and AFRC Institute of Plant Science, University of Sussex, Brighton, UK
The necessary conditions for the satisfactory parallel operation of spark gaps, with no transit time isolation between them, are deduced theoretically. Such a capacitor bank with closely connected parallel spark gaps has been operated successfully. The development of a 60 kv pressurized field-distortion spark with an inductance of 15-18 nH is described, and the influence of electrode arrangement and trigger circuit parameters on breakdown time and jitter has been investigated.
* Current address: 20 Pulcroft Road, Hessle, East Yorkshire, England. SICKLE cell disease, homozygous hemoglobin S I~~L globm disease (SS), and its genetic variant with the abnormal hemoglobin C(SC), is the most common inherited disease in tropical Africa. Reports show that approximately 25 per cent of the population of Nigeria are heterozygous for the sickle cell gene.1, 10, 14 Another 5 per cent are carriers of the gene for the abnormal hemoglobin C. Approximately 1.5 per cent of Nigerian children have homozygous sickle cell anemia and 0.5 per cent have sickle cell hemoglobin C disease. Patients with sickle cell disease frequently have episodes of pain in the abdomen, bones, and elsewhere. Bone pain, although most common in the limbs, may occur in .any bone of the body. These painful &dquo;crises&dquo; vary in severity from mild fleeting
The ability of some petroleum reservoir sands to conduct oil is decreased by interaction of the porous rock with water, usually water fresher than that coexisting with oil in rock interstices. Shales penetrated by drilling operations may swell upon interaction with relatively fresh water drilling liquids. The question of the relation of specific clay mineral content to reservoir sand water sensitivity has not been investigated in detail by other workers, although bentonitic clays often have been considered responsible. A selection of 90 core samples from widely scattered American oil fields has been analyzed for clay mineral content. Reservoirs of known water sensitivity history and others where no such problem exists are represented by the samples. Modern X-ray diffraction techniques were employed to determine clay mineral types, lattice expandability, and approximate amounts present. The main purpose was to test the hypothesis that there exists a direct relationship between content of 3-sheet, glycerol-expandable clay minerals and water-sensitive behavior. It was found that water sensitivity can be predicted with surprising accuracy by measuring the intensity of the X-ray diffraction peak of the glycerol-expanded basal plane spacing. Samples producing “moderate” or greater intensities of the glycerol-expanded peak were taken from sands that exhibited economically serious water-sensitive behavior. Large concentrations of nonexpandable kaolin, chlorite, and mica clay minerals did not produce serious water sensitivity effects in the absence of expandable minerals. A selection of samples from West Texas sands of Permian age were the only samples older than the Mesozoic found to contain expandable clay minerals. These expanded anomalously, possibly as a result of interstratification. The characteristic clay mineral suite might be employed as a geological marker to identify the Yates and Queen sands over a wide geographical area in Pecos, Ward, and Winkler counties of West Texas. A possible mechanism of the swelling of clay particles lining reservoir rock pores is discussed in terms of osmotic and Donnan membrane effects as applied to intraparticle swelling. The swelling of expandable clay mineral particles upon contact with relatively fresh water is postulated as the most general cause of water sensitivity difficulties encountered in petroleum production operations. Swollen particles restrict flow in rock pores, and minute, expanded lamellae break away to be dispersed in water within a pore and restrict flow further when they lodge in pore constrictions. Non-expandable clay mineral grains do interact specifically with water but are incapable of swelling and disintegrating to the same degree as those grains containing expandable minerals.
