This article aims to analyse the response of private forest owners to a series of extreme environmental disturbances in the Slovenian karst region in the period 2014–2016. Quantitative and ...qualitative analysis of empirical forest management data on response time and harvesting time, as well as interpretations of response drivers, led to the identification of forest commons as a fast and efficient type of forest ownership, despite almost a century of state suppression of their local institutions. Among the internal and external response drivers, a norm of responsibility and forest management competence were highlighted. Our study highlights the potential of forest commons for active forest management in Europe. A concerted response from private and state institutions should not only take into account economies of scale, but also traditional knowledge and local social norms
In silicon and other photonic integrated circuit platforms many devices exhibit a large polarization dependency, therefore a polarization beam splitter (PBS) is an essential building block to split ...optical signal to transversal electric (TE) and transversal magnetic (TM) modes. In this paper we propose a concept of integrated silicon-based PBS exploiting unique properties of all dielectric metamaterial cladding to achieve a high extinction ratio (ER) and wide bandwidth (BW) polarization splitting characteristics. We start from a structure (PBS-1) based on a directional coupler with metamaterial cladding combined with a bent waveguide with metamaterial cladding at the outer side in the role of a TE polarizer at the Thru port of the device. To increase BW we propose the improved concept (PBS-2) - a metamaterial compact dual Mach-Zehnder Interferometer structure in combination with the TE polarizer. Numerical simulations reveal that an exceptionally high ER over 35 dB can be achieved in a BW of 263 nm with insertion loss (IL) below 1 dB in case of PBS-2. The designed device has a footprint of 82 µm. Measurement results reveal that an ER > 30 dB is achievable in a BW of at least 140 nm (limited by the laser tuning range).
In this paper previously developed combined model of non-conformal layer growth is used to calculate positions in thin-film silicon solar cells where defective regions are expected to be formed ...within semiconductor layers, depending on the substrate texture. This enables omission of the textures leading to cells of poor electrical quality in the early process of optical optimisation of the cells and substrate texture design. Coupled with three-dimensional rigorous optical simulations, substrate textures are optimised with respect to high short-circuit current and defectless layer growth in micromorph silicon solar cells. Firstly, the approach of determination of defective regions is validated on realistic structures. Secondly, analysis of the effects of texture shape and of the material and the thickness of the grown layer is carried out. Thirdly, optimisation of substrate texture for micromorph type of solar cell is performed for sinusoidal, widened and semi-circular textures. Results on widened textures show, that smoothing/widening of the valleys does not always suppress the formation of defective regions in μc-Si:H and a-Si:H layers. A semi-circular type of the texture is determined to be the most appropriate for defectless absorbers in the analysed micromorph solar cells in substrate configuration, resulting also in up to 85% increase in short-circuit current of the bottom cell.
•Growth model used to predict defective regions within thin-film solar cells•Influence of the shape of surface textures on occurrence of defective regions shown•Smoothening/widening of the valleys is not always beneficial.•Optical optimisation with consideration of defective regions was performed.•Semi-circular texture is determined to have high potential for defectless growth.
Inorganic–organic perovskites like methylammonium-lead-iodide have proven to be an effective class of materials for fabricating efficient solar cells. To improve their performance, light management ...techniques using textured surfaces, similar to those used in established solar cell technologies, should be considered. Here, we apply a light management foil created by UV nanoimprint lithography on the glass side of an inverted (p-i-n) perovskite solar cell with 16.3% efficiency. The obtained 1 mA cm–2 increase in the short-circuit current density translates to a relative improvement in cell performance of 5%, which results in a power conversion efficiency of 17.1%. Optical 3D simulations based on experimentally obtained parameters were used to support the experimental findings. A good match between the simulated and experimental data was obtained, validating the model. Optical simulations reveal that the main improvement in device performance is due to a reduction in total reflection and that relative improvement in the short-circuit current density of up to 10% is possible for large-area devices. Therefore, our results present the potential of light management foils for improving the device performance of perovskite solar cells and pave the way for further use of optical simulations in the field of perovskite solar cells.
Forest commons in Slovenia are a poorly known indigenous institution for common resource management. They are a functional entity linked to a specific community that establishes interpersonal and ...intergenerational ties, as well as a link to the resource. We refer to shared ownership of resource, once made of pastures; today forests prevail. Collective property management remained despite community changes and legislation development. Today registered forest commons represent approximately one-third of those that existed before 1945. We highlight seven developmental turns to explain their revival. Six indicators are used in the analysis of current conditions. Forest commons are a potentially effective response to forest management challenges in Slovenia but also a potential model of social cohesion, rational resource use, and a balance between forest use and conservation. However, they are plagued by state ignorance, which hinders statistically sound analyses.
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