1,322 research outputs found
Community Organisations, Misiones and Integration of Barrios of Caracas: The Case of the CAMEBA Upgrading Project
The paper is an attempt to analyse the likely effects of compensatory social programmes such as Misiones Bolivarianas on community organisations in barrios and their participation in the planning and implementation of barrio upgrading projects, based on the case of the CAMEBA project in Caracas, Venezuela.
The low level of community (target group) participation in Project CAMEBA has been compounded by a profoundly paternalistic approach of the national government that promised immediate relief and benefits in the form of compensatory programmes thus reinforcing habitual dependency amongst the poor people. These immediate-benefit programmes seem to have had an inhibiting effect on the community organisation and participation in the upgrading project, which had long term objectives and had aspired to create sustainable self-reliant communities in the project’s intervention areas. Such conclusion is reinforced by the results of the survey, which clearly shows that the awareness of the community regarding compensatory programmes is by and large greater than that of the upgrading project, even though project CAMEBA implementation started about four years before the apperance of the Misiones Bolivarianas.
This situation has somehow hindered the process of community organisation which in any case involves training of communities to be legitimate and autonomous by getting rid of their chronic dependency syndrome.
IHS Workin
Marine-friendly antifouling coating based on the use of a fatty acid derivative as a pigment
This study was devoted to examining the application of copper dodecanoate as a non-contaminant antifouling pigment due to its low copper content and fatty acid nature. For this purpose, antifouling paints with mono-component epoxy resin and rosin matrixes were formulated, and their antifouling efficiency was evaluated. Before its incorporation into the different formulations, the synthesized pigment was characterized. Immersion tests in a marine environment were carried out for 12 months to evaluate the antifouling efficiency of the developed paints; the results were compared with those from a commercial paint. The antifouling efficiency of the new epoxy formulation was found to be considerably higher than that of the rosin formulation and very similar to that of the commercial paint. Most importantly, the release of copper from the epoxy paint formulated with copper dodecanoate was 73.5% lower than that of the commercial paint, suggesting prolonged activity of the developed paint.Peer ReviewedPostprint (published version
Estudio comparativo de la estabilización de un suelo plastico con cal y/o cemento portland
En este trabajo se comentan las determinaciones practicadas en la estabilización de un suelo plástico con cemento portland y con cal hidratada en polvo, así como la estabilización de dicho suelo con cemento portland, previa corrección con cal, Los gráficos muestran los resultados obtenidos en dicha estabilización.
Se comentan los posibles procesos físico-químicos que tendrían lugar entre el suelo y los estabilizantes, para dar lugar a la mencionada estabilización.The present repot refers to the determinations made over one plastic soil, estahilized with portlandcement and with hidrated lime, as soon as the stabilization of the same soil with Portland cement, foregoing corrected with hidrated lime.
The graphs includes the results obtained in these determinations.
The work contains some ideas on the physicochemical proccesses that would explains the mentioned stabilization
Metallic Species In Ambient Air Particles. PM10
In the present work metallic species of particulate matter(PM10) present in an urban area of Gran Canaria Island were quantified. Experimental measurements were carried out from October 2004 to September 2005 with a total of 53 samples (4 or 5 per month). PM10 was collected in fiber filters using high volume samplers. The average concentration was 32,6 ± 19,6 μg/m3. PM10 was determined gravimetrically. Concentrations of metallic elements were analized by atomic emission spectrophotometry using an ICP-OES. Two categories of elements were found: “abundant” and “scarce”. The examined elements were characterized according to their origin from natural or anthropogenic emissions on the basis of enrichment factors. Factor analysis of elemental composition pattern was also used to identify possible pollution source-types
Organocatalytic strategies for the development of the enantioselective inverse-electron-demand hetero-Diels-Alder reaction
Cycloaddition reactions, in particular Diels-Alder reactions, have attracted a lot of attention from organic chemists since they represent one of the most powerful methodologies for the construction of carbon-carbon bonds. In particular, inverse-electron-demand hetero-Diels-Alder reactions have been an important breakthrough for the synthesis of heterocyclic compounds. Among all their variants, the organocatalytic enantioselective version has been widely explored since the asymmetric construction of diversely functionalized scaffolds under reaction conditions encompassed within the green chemistry field is of great interest. In this review, a profound revision on the latest advances on the organocatalytic asymmetric inverse-electron demand hetero-Diels-Alder reaction is shownWe are grateful to the Spanish Government (CTQ2015-64561-R
and RTI2018-095038-B-I00), “Comunidad de Madrid” and European Structural Funds (S2018/NMT-4367). J.A.F.-S. thanks the
Spanish Government for a Ramón y Cajal contract. V.L.-M.
thanks Universidad Autónoma de Madrid for a predoctoral
fellowship (FPI-UAM
Shearing interferometry via geometric phase
We propose an approach based on geometric phase for per- forming several types of shearing interferometry through a robust, compact, common-path setup. The key elements are two identical parallel plates with spatially varying birefringence distributions, which perform the shearing by writing opposite geometric phases on the two circular polarization components of the linearly polarized incident wavefront. This setup allows the independent control of the shearing magnitude and relative phase of the two wavefront replicas. The approach is first illustrated for the simplest case of lateral shearing, and then extended to other geometries where the magnitude and direction of the shear vary smoothly over the wavefront
Multiply Folded Graphene
The folding of paper, hide, and woven fabric has been used for millennia to
achieve enhanced articulation, curvature, and visual appeal for intrinsically
flat, two-dimensional materials. For graphene, an ideal two-dimensional
material, folding may transform it to complex shapes with new and distinct
properties. Here, we present experimental results that folded structures in
graphene, termed grafold, exist, and their formations can be controlled by
introducing anisotropic surface curvature during graphene synthesis or transfer
processes. Using pseudopotential-density functional theory calculations, we
also show that double folding modifies the electronic band structure of
graphene. Furthermore, we demonstrate the intercalation of C60 into the
grafolds. Intercalation or functionalization of the chemically reactive folds
further expands grafold's mechanical, chemical, optical, and electronic
diversity.Comment: 29 pages, 10 figures (accepted in Phys. Rev. B
- …