Sub-THz Vibrational Dynamics in Ordered Mesoporous Silica Nanoparticles

The vibrational dynamics in the sub-THz range of mesoporous silica nanoparticles (MSNs) having ordered cylindrical mesopores was investigated. MCM-41 and SBA-15 particles were synthesized, and their structure was determined using scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), N₂ physisorption analyses, and Raman scattering. Brillouin scattering measurements are reported and enabled determining the stiffness of the silica walls (speed of sound) using finite element calculations for the ordered mesoporous structure. The relevance of this approach is discussed based on the comparison between the numerical and experimental results and previous works reported in the literature.

Synthesis of low cost organometallic-type catalysts for their application in microbial fuel cell technology

Microbial fuel cells (MFCs) are a promising technology that generates electricity from several biodegradable substrates and wastes. The main drawback of these devices is the need of using a catalyst for the oxygen reduction reaction at the cathode, which makes the process relatively expensive. In this work, two low cost materials are tested as catalysts in MFCs. A novel iron complex based on the ligand n-phenyledenparaethoxy aniline has been synthesized and its performance as catalyst in single chamber MFCs containing ionic liquids has been compared with a commercial inorganic material such as Raney nickel. The results show that both materials are suitable for bioenergy production and wastewater treatment in the systems. Raney nickel cathodes allow MFCs to reach a maximum power output of 160 mW.m^-3 _anode, while the iron complex offers lower values. Regarding the wastewater treatment capacity, MFCs working with Raney nickel-based cathodes reach higher values of chemical oxygen demand removal (76%) compared with the performance displayed by the cathodes based on Fe-complex (56%).

[Education of health personnel in the design of humanitarian actions; the experiences of a non-governmental organization]

The aim of this study is to ascertain the importance that a Non-Governmental Organisation (NGO) such as the French section of Doctors Without Borders, (MSF Médecins Sans Frontières), gives to the education of health staff within for humanitarian aid interventions. The study was carried out at the headquarters of this NGO and consisted in classifying educational activities, analyzing assignment reports and conducting interviews with the staff at the headquarters of the organization. Accordingly, an educational activity can be identified in 85% of the 41 assignments listed in 1998. Nearly half of these were carried out in geographical areas that are classified as stable. The qualitative study of educational activities underlines the importance of the stages preceding the implementation of the actual educational program (needs analysis, feasibility study). During interviews with staff at the MSF headquarters, the majority of the 22 interviewees stated that educational activities contribute to the quality of aid activities in situ. Nearly a third of the interviewees, however, felt that educational methods used were too useless. It would seem, therefore, that the degree of importance attached to education and the actual educational methods practiced differ totally for each of the association's standard forms humanitarian interventions (urgency, post-urgency, development for technical assistance).