Adsorption Behaviour of [(4-Hydroxy-6-methyl-2-oxo-2Hpyran- 3-yl)-(4-methoxy-phenyl)-1methyl]-urea on Stainless Steel in Phosphoric Media

The adsorption of [(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-(4-methoxy-phenyl)- methyl]-urea on iron in phosphoric media was studied by using electrochemical technique. The adsorption mechanism was investigated using adsorption isotherms. The experimental data fit localized adsorption models. The values for free energy of adsorption, o DGads , were also calculated at each surface coverage, �, of the studied compound by applying the mathematical model of Bockris – Swinkels adsorption isotherm. The variation of free energy of adsorption o ads DG with surface coverage, �, was interpreted in terms of deviation from ideal condition assumed in Langmuir model. A possible adsorption model of HPU2 molecules on to the metal surface was suggested

It Does Matter What You Do: How Practical Choices Reflect Theology

(Excerpt) We would all, I trust, agree with the centrality of baptism for Lutheran theology and its importance for Lutheran liturgical renewal. Yet, how many of us are from parishes where baptisms, if done during the Sunday assembly at all, are at small, out of the way fonts, with a few drops of water, no candles or oil, and little or no congregational involvement? Certainly, the baptism is valid, but is it salutary? Have we done any more than meet the lifetime minimum requirement of grace ? Have we lost a wonderful opportunity to celebrate the richness of grace poured out in baptism, not only on the baptized but on the community

Reflections on becoming a teacher and the challenges of teacher education

In this lecture, the context and conditions of becoming a teacher from the time of being selected into the programme, through the process of training and being retained to teach are discussed within the framework of Teacher Education in Nigeria. First, the concepts and the history of teacher education are examined. Then, some critical issues as well as my personal research efforts on teacher education are discussed. Finally, recommendations for meeting the challenges of Teacher Education in Nigeria are made

Role of vertical migration in biogenic ocean mixing

Recent efforts to empirically measure and numerically simulate biogenic ocean mixing have consistently observed low mixing efficiency. This suggests that the buoyancy flux achieved by swimming animals in the ocean may be negligible in spite of the observed large kinetic energy dissipation rates. The present letter suggests that vertical migration across isopycnals may be necessary in order to generate overturning and subsequent mixing at length scales significantly larger than the individual animals. The animal-fluid interactions are simulated here using a simplified potential flow model of solid spheres migrating vertically in a stably stratified fluid. The interaction of successive solid bodies with each parcel of fluid is shown to lead, under certain conditions, to vertical displacement of the fluid parcels over distances much larger than the individual body size. These regions of displaced fluid are unstably stratified and, hence, amenable to large-scale overturning and efficient mixing

Optimal vortex formation as a unifying principle in biological propulsion

I review the concept of optimal vortex formation and examine its relevance to propulsion in biological and bio-inspired systems, ranging from the human heart to underwater vehicles. By using examples from the existing literature and new analyses, I show that optimal vortex formation can potentially serve as a unifying principle to understand the diversity of solutions used to achieve propulsion in nature. Additionally, optimal vortex formation can provide a framework in which to design engineered propulsions systems that are constrained by pressures unrelated to biology. Finally, I analyze the relationship between optimal vortex formation and previously observed constraints on Strouhal frequency during animal locomotion in air and water. It is proposed that the Strouhal frequency constraint is but one consequence of the process of optimal vortex formation and that others remain to be discovered

Urban droughts and floods in Maiduguri: twin hazards of a variable climate

Maiduguri, an important city in the Sudano-Sahelian zone of West Africa, experiences both drought and floods. Although droughts are more popular, floods are a seasonal occurrence in parts of the city in the average rainy season. Both hazards exert a heavy toll on their victims. Present response to the hazard problems is characterised by a fire-fighting approach which does little about future occurrence. Much of the perception and response is spiritual and stops short of needed structural and organisational programmes for effective mitigation of hazards. Future occurrences of drought and flood may have more adverse effects as land use in the city becomes more complex and agricultural and water supply system comes to depend heavily on surfacial sources. Future effects will also depend on the socio-economic conditions of the people at risk and the capacity of those who help them. Governments and people need to work together to reduce drought and flood hazards