Politicas agrarias y estrategias campesinas en la Cuenca del Canete : anexos 14 a 19

Ce document présente des méthodologies d'enquêtes utilisées dans la microrégion de Yauyos (Vallée du haut Canete) afin de définir la communauté paysanne en tant qu'unité d'observation et d'analyser le système communal dans ses fonctions de pouvoir et d'organisation sociale. Sont également étudiées, les destinations de la production agropastorale de la famille paysanne : autoconsommation, troc, vente ainsi que les circuits de commercialisation

In-situ multicore fibre-based pH mapping through obstacles in integrated microfluidic devices

Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As a proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor.Comment: 12 pages of main draft with 10 figures, 2 pages of supplementary information with 3 figures. Total 14 page

Review of Microfluidic Devices and Imaging Techniques for Fluid Flow Study in Porous Geomaterials

Understanding transport phenomena and governing mechanisms of different physical and chemical processes in porous media has been a critical research area for decades. Correlating fluid flow behaviour at the micro-scale with macro-scale parameters, such as relative permeability and capillary pressure, is key to understanding the processes governing subsurface systems, and this in turn allows us to improve the accuracy of modelling and simulations of transport phenomena at a large scale. Over the last two decades, there have been significant developments in our understanding of pore-scale processes and modelling of complex underground systems. Microfluidic devices (micromodels) and imaging techniques, as facilitators to link experimental observations to simulation, have greatly contributed to these achievements. Although several reviews exist covering separately advances in one of these two areas, we present here a detailed review integrating recent advances and applications in both micromodels and imaging techniques. This includes a comprehensive analysis of critical aspects of fabrication techniques of micromodels, and the most recent advances such as embedding fibre optic sensors in micromodels for research applications. To complete the analysis of visualization techniques, we have thoroughly reviewed the most applicable imaging techniques in the area of geoscience and geo-energy. Moreover, the integration of microfluidic devices and imaging techniques was highlighted as appropriate. In this review, we focus particularly on four prominent yet very wide application areas, namely “fluid flow in porous media”, “flow in heterogeneous rocks and fractures”, “reactive transport, solute and colloid transport”, and finally “porous media characterization”. In summary, this review provides an in-depth analysis of micromodels and imaging techniques that can help to guide future research in the in-situ visualization of fluid flow in porous media

Synthesis of TiO2-x/W18O49 Hollow Double-shell and Core-shell Microspheres for CO2 Photoreduction under Visible Light

TiO2x/W18O49 with core–shell or double-shelled hollow microspheres were synthesized through a facile multi-step solvothermal method. The formation of the hollow microspheres with a doubleshell was a result of the Kirkendall effect during the solvothermal treatment with concentrated NaOH. The advanced architecture significantly enhanced the electronic properties of TiO2x/ W18O49, improving by more than 30 times the CO2 photoreduction efficiency compared to the pristine W18O49. Operando DRIFTS measurements revealed that the yellow TiO2x was a preferable CO2 adsorption and conversion site

An innovative quick solidifying technique for the forensic investigation of brain circulation using addition silicones

Post-mortem study of the brain is extremely relevant to medico-legal autopsies. However, it can be difficult to handle due to its fragility. This article presents a study on the development of an arterial solidifying technique that can be applied to analyze arterial circulation, consequently easing the handling and later diagnosis of diseases in this anatomical site. Vinylpolysiloxane silicone is introduced into the internal carotid arteries until it completely fills the arterial tree, creating a detailed model of the arterial's internal anatomy. This technique is fast, easy to apply and requires no previous tissue fixation. In addition, it allows for further toxicological and pathological tests. In conclusion, this technique represents a simple, sensitive and efficient method to employ in conventional autopsies, which can help in the diagnosis of death

Hysteresis loops in CuO

Hysteresis loops at room temperature have been observed and investigated in nanostructures and nanoparticles ofCupric Oxide (CuO) with same average grain size. Morphological and structural properties of the studied sampleswere characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). Energy-dispersive X-rayspectroscopy (EDS) was employed to analyze the possible presence of impurities. Mean crystallite diameter sizeswere determined using Rietveld refinement analysis of the diffraction patterns. The results suggest that hysteresisloops morphology depend on the process to obtain each sample, which not only affect grain size, but also mayinduce anisotropic forms and residual microstrains.Lazos de histéresis a temperatura ambiente han sido observados y estudiados en nanoestructuras y nanopartículas de óxido cúprico (CuO) con el mismo tamaño promedio de cristalito. Las propiedades morfológicas y estructurales de las muestras fueron caracterizadas usando difracción de rayos X y microscopía electrónica de barrido (SEM). La presencia de impurezas ha sido descartada a partir de resultados de espectrometría de dispersión de energía de rayos X (EDS). El tamaño promedio de los cristalitos ha sido determinado usando el método de refinamiento de Rietveld de los patrones de difracción. Los resultados sugieren que las características de los lazos de histéresis dependen del proceso de obtención de las muestras, el que no sólo influye en el tamaño de grano sino también puede inducir formas y micro tensiones residuales anisotrópicas.Instituto de Física La PlataFacultad de IngenieríaConsejo Nacional de Investigaciones Científicas y Técnica

Hysteresis loops in CuO

Hysteresis loops at room temperature have been observed and investigated in nanostructures and nanoparticles ofCupric Oxide (CuO) with same average grain size. Morphological and structural properties of the studied sampleswere characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). Energy-dispersive X-rayspectroscopy (EDS) was employed to analyze the possible presence of impurities. Mean crystallite diameter sizeswere determined using Rietveld refinement analysis of the diffraction patterns. The results suggest that hysteresisloops morphology depend on the process to obtain each sample, which not only affect grain size, but also mayinduce anisotropic forms and residual microstrains.Lazos de histéresis a temperatura ambiente han sido observados y estudiados en nanoestructuras y nanopartículas de óxido cúprico (CuO) con el mismo tamaño promedio de cristalito. Las propiedades morfológicas y estructurales de las muestras fueron caracterizadas usando difracción de rayos X y microscopía electrónica de barrido (SEM). La presencia de impurezas ha sido descartada a partir de resultados de espectrometría de dispersión de energía de rayos X (EDS). El tamaño promedio de los cristalitos ha sido determinado usando el método de refinamiento de Rietveld de los patrones de difracción. Los resultados sugieren que las características de los lazos de histéresis dependen del proceso de obtención de las muestras, el que no sólo influye en el tamaño de grano sino también puede inducir formas y micro tensiones residuales anisotrópicas.Instituto de Física La PlataFacultad de IngenieríaConsejo Nacional de Investigaciones Científicas y Técnica