Chemical and mineralogical characterization and ceramic suitability of raw feldspathic materials from Dschang (Cameroon)

The chemical and mineralogical characterization of raw feldspathic materials from Dschang (Cameroon) was realized by means of X-ray diffraction, differential thermal analyses, optical and scanning electron microscopies, and analytical techniques. It was found that these materials consist of albite (43 ± 3 wt.%), microcline (41 and 26 wt.%), quartz (14.5 ± 1.5 wt.%), plagioclase (oligoclase type) (6 and 12 wt.%) and a minor content of biotite. The amount of fluxing oxides is about 12 wt.% and those of pigments are quasi-null. The ceramic suitability of these materials was assessed in the light of the obtained chemical data and physical characteristics (fusibility, viscosity, colour). The results showed that these raw materials are convenient, as fluxing compounds, for manufacturing white ceramic.KEY WORDS: Raw feldspathic materials, Mineralogy, Chemical composition, Ceramic suitability, Cameroon   Bull. Chem. Soc. Ethiop. 2010, 24(1), 39-46

Examining the myths of connected and autonomous vehicles: analysing the pathway to a driverless mobility paradigm

Connected and autonomous vehicles (CAVs) could become the most powerful mobility intervention in the history of human race; possibly greater than the conception of the wheel itself or the shift from horse-carriages to automobiles. Despite CAVs' likely traffic safety, economic, environmental, social inclusion and network performance benefits their full-scale implementation may not be as predictable, uncomplicated, acceptable and risk-free as it is often communicated by a large share of automotive industries, policy-makers and transport experts. Framing an 'unproven', 'disruptive' and 'life-changing' intervention, primarily based on its competitive advantages over today's conventional automobile technologies, may create misconceptions, overreaching expectations and room for errors that societies need to be cautious about. This article 'tests' eleven myths referring to an overly optimistic CAVs' development and adoption timeline. This approach highlights unresolved issues that need to be addressed before an inescapable CAV-based mobility paradigm transition takes place and provides relevant policy recommendations on how to achieve that

Effet de la fertilisation minerale et organique sur le rendement en fruits du piment (Capsicum annuum L.; Solanaceae) en zone forestiere de basse altitude au Cameroun

A study on the effect of mineral and organic fertilizations on fruits yield of pepper (Capsicum annuum L.) was carried out in Cameroon. Three types of fertilizers: urea (46 %N), single superphosphate (16 %P2O5), and potassium sulphate (48 %K2O) were used alone, or in combination with each other and a bulk fertilizer NPK (19-4-16) was also formulated in order to optimize fruit yield. Poultry manure was used as organic fertilizer. During crop growth, plant height, canopy width, planting-flowering interval, flowering-fruiting period and the number and weight of fruits harvested were measured. The results show that bulking of the 3 single fertilizers, applied 4 times during the cropping period produced highly significant effects on all plant growth parameters. Significant differences were also observed on parameters of reproduction when NPK was applied 3 to 4 times during the cropping period. Furthermore, NPK, regularly broadcasted 4 times under plant canopy, gave the highest fruit yield. This latest treatment yielded the highest income and benefit-cost ratio. The organic fertilization had a higher fruit yield and higher benefit-cost ratio than many chemical fertilizer treatments.Keywords: Capsicum annuum L., fertilizer, formulation, fertilizationAgronomie Africaine 24 (3) : 231 - 240 (2012

The Journey to R4D: An institutional history of an Australian Initiative on Food Security in Africa

Internal Revie

Analysis of Constraints to Agricultural Production in the Sudano Savanna Zone of Cameroon and Implication for Research Priority Setting

A participatory rural appraisal (PRA) survey approach was used to identify the major constraints to agricultural production and to describe the major production systems in the sudano savanna and sudano sahelian zone of northern Cameroon. Relative emphasis was placed on the household level characterization to have a better understanding of the land use system, farmers' constraints to production and opportunities, so as to better target agricultural technologies and interventions in this vast agro-ecological zone. It was noted that, large variations exist in agriculture management practices between agro-ecological zones, among villages and households in terms of access to resources, such as labour, fertilizers, livestock, farm equipment, and land. Intensive and extensive farming practices might co-exist within the same village and households. The mains sources of vulnerability were identified. Results are used to set research priorities which will be directed towards the need of the majority of area's population; the improvement of sustainable food and feed crop production

Assessment of the potential effect of some streams properties on the isolated Aeromonas hydrophila strains susceptibility against some β-Lactams and Sulfamids

The isolation and characterization of A. hydrophila strains were carried out a given stream located in the equatorial zone in Cameroon (Central Africa), during the mild rainy season and the mild dry season. The water physicochemical parameters measured were temperature, pH, electrical conductivity, color, turbidity and suspended solids. It has been noted that bacterial abundances as well as the values of physicochemical parameters undergoes temporal variations. Antimicrobial susceptibility tests showed that the means diameters of inhibition with Oxacillin, Ceftriazone, Penicellin, Sulfamethoxazol-trimethoprim, Chloramphenicol, Imipenem, Amoxicillin-Clavulanic acid and Cefazolin were 6.44, 21, 6.63, 9.58, 15.37, 22.18, 14.29 and 10.26 mm respectively. 100% of strains tested were resistant to Penicillin, 89.47 % resistant to Oxacillin, 68.42% resistant to Sulphamethoxazole-trimetroprim and 63.15% were resistant to Cefazolin. There were 54.60% cases of antibiotic resistance, 24.34 % of intermediate sensitivity and 21.05% of sensitive strains against the tested antibiotics. The encoded redundancy analysis indicates that the percentage of the variation explained on the canonical axes is of 47.8% for the F1 axis and 25.9% for the F2 axis, for an accumulated percentage of 73.7%. The suspended solids, the Ceftriazon and Chloramphenicol are correlated to the F1 axis in positive coordinates, and the Temperature and Amoxicillin-Clavulanic acid in negative coordinates. The correlation test between the water physicochemical characteristics and the inhibition diameters of antibiotics showed some significant correlations (P<0.05). The regulation of bacterial genes would be regulated by complex mechanisms. Although many factors implied are linked to the bacterial cell, others may belong to the closed environment