Publications

Biodiesels are biofuels made from renewable sources such as vegetable oils originating from plants and animal fats. Transesterification reaction is carried out by reacting triglycerides in oil/fat with an alcohol in presence of a catalyst. Important process variables are reaction temperature, time, reactant concentration and the catalyst. Catalysts can be homogeneous or heterogeneous. Homogeneous catalysts are liquid phase ionic acid and base, enzymes, and non-ionic organic base compounds. Heterogeneous catalysts are acid and base type. Examples of acid heterogeneous catalysts are ion-exchange resins, tungstated and sulphated zirconia, metal complexes and zeolite. Base heterogeneous catalysts consist of metal oxides in pure form or over support, zeolites, clays and nonoxides. Paper gives a brief introduction of catalytic transesterification process and a detailed review of solid basic catalysts. It is found that these catalysts are selective to feed and preparation method. Acid solid catalysts are suitable for high free fatty acid feed. Basic solid catalyst give a better yield compared to acid solid catalysts but lead to soap formation if feed has high free fatty acid.

The study describes the knowledge of and attitudes toward substance use among street-involved youth in Kenya, and how they relate to their substance use practices. In 2011, 146 children and youth ages 10–19 years, classified as either children on the street or children of the street were recruited to participate in a cross-sectional survey in Eldoret, Kenya. Bivariate analysis using χ2 or Fisher's Exact Test was used to test the associations between variables, and multiple logistic regression analysis was used to identify independent covariates associated with lifetime and current drug use. The study's limitations and source of funding are noted.