Estudios reales en banco de pruebas de la Casa ETH de Recursos Naturales – protección superficial de la madera para aplicaciones exteriores

The increasing demand for sustainable construction materials used in urban areas calls for novel wood protective coatings, which retain the natural appearance of wood while minimizing maintenance intervals. This work reports on three different wood surface modification processes and evaluates their protective effect against weathering after installation at a testing façade of the ETH House of Natural Resources (HoNR), a recently opened living lab located in Zürich, Switzerland. We monitored the discoloration upon outdoor exposure of subsequently improved generations of thin metal oxide coatings developed in our lab. We target almost transparent and durable coatings with water repellent properties to diminish discoloration due to UV light and biological attack. This should lead to wooden facades with increased reliability and thereby boost an enhanced utilization of the renewable and CO2 storing resource wood.La creciente demanda de materiales de construcción sostenibles en áreas urbanas requiere nuevos recubrimientos protectores de madera, que conservan el aspecto natural de la madera al tiempo que minimizan los periodos de mantenimiento. Este trabajo presenta tres procesos diferentes de modificación de superficies de madera y evalúa su efecto protector contra la intemperie después de la aplicación en una fachada de prueba de la Casa de Recursos Naturales ETH (HoNR), un living lab recientemente abierto ubicado en Zürich, Suiza. Se controló la decoloración después de la exposición al aire libre de las formulaciones mejoradas de revestimientos delgados de óxido de metal desarrollados en el laboratorio. Se hizo hincapié en recubrimientos casi transparentes y duraderos con propiedades hidrófugas para disminuir la decoloración debida a la luz ultravioleta y al ataque biológico. Esto debería conducir a fachadas de madera con una mayor durabilidad y, por lo tanto, impulsar una utilización mejorada de recursos renovables y de almacenamiento de CO2

How simple can a model of an empty viral capsid be? Charge distributions in viral capsids

We investigate and quantify salient features of the charge distributions on viral capsids. Our analysis combines the experimentally determined capsid geometry with simple models for ionization of amino acids, thus yielding the detailed description of spatial distribution for positive and negative charge across the capsid wall. The obtained data is processed in order to extract the mean radii of distributions, surface charge densities and dipole moment densities. The results are evaluated and examined in light of previously proposed models of capsid charge distributions, which are shown to have to some extent limited value when applied to real viruses.Comment: 10 pages, 10 figures; accepted for publication in Journal of Biological Physic

Ceramic Water Filter for Point-Of-Use Water Treatment in Developing Countries: Principles, Challenges and Opportunities

Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces

Non-Scanning magnetic field imaging with laser-pumped atomic magnetometer

We present first results on the imaging of the two dimensional magnetic field distributions using a recently developed magnetic field imaging camera (MFIC). The instrument is based on laser-pumped atomic magnetometry with an alkali vapour in a buffer gas. The device provides millimetre spatial and sub-second time resolution, and allows mapping the magnetic field from circa 2 cm2 surfaces. We apply the MFIC to image magnetic field patterns of deposited superparamagnetic nanoparticles (SPIONs) and quantify the achieved sensitivity. We address the applicability of the instrument to in-vitro and in-vivo imaging of SPIONs distributions in biological tissue and small animals