The Tax Reform Experience of Kenya

tax reform, Kenya, inequality, trade

Static and dynamic strain sensing using a polymer : carbon nanotube film strain sensor

The search for new multipoint, multidirectional strain sensing devices has received a new impetus since the discovery of carbon nanotubes. The excellent electrical, mechanical, and electromechanical properties of carbon nanotubes make them ideal candidates as primary materials in the design of this new generation of sensing devices. Carbon nanotube based strain sensors proposed so far include those based on individual carbon nanotubes for integration in nano or micro elecromechanical systems (NEMS/MEMS) [1], or carbon nanotube films consisting of spatially connected carbon nanotubes [2], carbon nanotube - polymer composites [3,4] for macroscale strain sensing. Carbon nanotube films have good strain sensing response and offer the possibility of multidirectional and multipoint strain sensing, but have poor performance due to weak interaction between carbon nanotubes. In addition, the carbon nanotube film sensor is extremely fragile and difficult to handle and install. We report here the static and dynamic strain sensing characteristics as well as temperature effects of a sandwich carbon nanotube - polymer sensor fabricated by infiltrating carbon nanotube films with polymer

Effect of fibre treatments on mechanical properties of flax/tannin composites

Due to the inherent environmental benefits of using natural resin (tannin) and natural fibre (flax), flax/tannin composites could be potentially used for vehicle applications. One of the main limitations is the hydrophilic property of flax, resulting in the poor fibre/hydrophobic matrix interface quality. Alkali, acetylation, silane treatment and enzymatic treatment were selected to modify non-woven flax mats to prepare the composites. The fibre morphology was studied through scanning electronic microscopes (SEM). The effects of fibre pre-treatments on dynamic and static mechanical properties of composites were investigated through adequate experiments, such as dynamic mechanical analysis (DMA) and static tensile testing. The modified rougher fibre surface broadened the glass transition peaks of composites due to the improved surface adhesion. However, there is no big improvement of tensile strength after modifications. The pure NaOH (sodium hydroxide) treated composites remain the tensile properties and offer good flax/tannin wettability

Mavens and their potential role in the diffusion of marketing information

Small ruminants play an important social and economic role in the lives of many pastoralists who inhabit many parts of Northern Kenya. The area is poorly served by modern communication services although things are slowly changing as mobile telephone services are rolled into these areas. This possibility will likewise improve the chances of providing this population with up-to-date market intelligence which in turn should improve the returns from the sale of livestock in distant markets. To operationalise this, the use of the internet as well as SMS delivered market intelligence through the National Livestock Marketing Information System (NLMIS) was launched in 2007. As a novel idea in the region, it was expected that information about its existence would pass through a series of intermediaries such as mavens. Based on a study of 250 pastoral households, this paper attempts to explore the concepts of mavens, opinion leadership and innovativeness in the marketing of small ruminants from the larger Marsabit and Isiolo Districts of Eastern Province, Kenya. It concludes that though the NLMIS is still relatively unknown, the presence of market mavens who in this data are indistinguishable from opinion leaders could catalyze the spread and eventual use of the system.Market mavens, Opinion leaders, Innovativeness

Mechanical properties of three-phase polyamide 6 nanocomposites

This work focus on the mechanical properties of three-phase nanocomposites using multiscale reinforcements. The influence of the nano-fillers content, as well as the temperature were studied. Polyamide-6 reinforced with short glass fibre 30 wt.% and with an addition of nanoclay (montmorillonite) and/or nanosilica (SiO2) were tested in order to characterise their tensile properties at room temperature and at 65oC just above the polyamide 6 glass transition temperature. SEM analysis were conducted on the fracture surface of the tensile bars. SEM investigations showed the importance of the interaction matrix/filler for the material behaviour. Our study also shows that the increase of OMMT percentage in polyamide-6/glass fibre composite made the material more brittle and had a negative effect on the tensile properties. Further, for the silica-based nanocomposites, an optimum was found for a nanofillers content of 1wt.%

Nanofiller Fibre-Reinforced Polymer Nanocomposites

In this work, the technology of nano and micro-scale particle reinforcement concerning various polymeric fibre-reinforced systems including polyamides (PA), polyesters, polyurethanes, polypropylenes and high performance/temperature engineering polymers such as polyimide (PI), poly(ether ether ketone) (PEEK), polyarylacetylene (PAA) and poly p-phenylene benzobisoxazole (PBO) is reviewed. When the diameters of polymer fibre materials are shrunk from micrometers to submicrons or nanometers, there appear several unique characteristics such as very large surface area to volume ratio (this ratio for a nanofibre can be as large as 103 times of that of a microfibre), flexibility in surface functionalities and superior mechanical performance (such as stiffness and tensile strength) compared with any other known form of the material. However, nanoparticle reinforcement of fibre reinforced composites has been shown to be a possibility, but much work remains to be performed in order to understand how nanoreinforcement results in dramatic changes in material properties. The understanding of these phenomena will facilitate their extension to the reinforcement of more complicated anisotropic structures and advanced polymeric composite systems

Development administration and decentralisation: some administrative and political considerations

The paper discusses the meaning of development administration suggesting that it is closer in meaning to political development than to traditional public administration. If then goes on to speculate on the adequacy of decentralisation as a response to specific problem areas of development administration. The underlying argument is that decentralisation is not a panacea. Rather it must be accompanied by a high degree of political commitment from all concerned, and in this sense, it is an issue in underdevelopment