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The aim has been to assess social acceptance and the opportunity to use renewable energy sources by rural area residents, as exemplified by the rural municipality of Dołhobyczów. The results of the questionnaire survey on renewable energy sources used by farmsteads have been presented. Solar energy (solar collectors, solar dryers) is most often used in this area. Some farmers have come into possession of biomass boilers in their farmsteads.

Abstract Solutions containing hydrofluoric acid (HF), hydrochloric acid (HCl), and hydrogen peroxide (H2O2) were investigated as novel acidic, NOx-free etching mixtures for texturing of monocrystalline silicon wafers. High etch rates of up to 13.3 nm s−1 were observed at room temperature, which are comparable to the etch rates of KOH-IPA solutions. The silicon surface was investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), indicating pyramidal textures for diamond wire and SiC-slurry sawn as well as saw-damage etched (polished) wafers. Non-stirred baths generate random pyramidal structures while constantly stirred solutions generate novel random inverted pyramidal surface structures. The light trapping efficiency of wafers etched by the HF-HCl-H2O2 solutions was compared by UV/vis-reflectivity measurements to KOH/i-propanol specimens indicating lower reflectivities for the HF-HCl-H2O2-treated samples. Using the ‘wafer ray tracer’ (pvlighthouse.com) the light absorption properties of monomodal and random inverted pyramid structures were simulated and compared to well-known random and monomodal textures for PERC solar cells, clearly indicating the best performance for random inverted pyramids. Besides, simulation of a PERC solar cell on a roof top at our university was performed, indicating improved performance, especially for random inverted pyramid textures.

The orbital occupation, which is the centerpiece of both self-interaction and several metal-insulator transition analyses, as well as of the local density or generalized gradient approximation with a Hubbard term, is not well defined, in the sense that it is partially ambiguous. A general treatment can be applied to both strongly and weakly correlated systems. When it is applied to an intermediate- and partially filled band within of the host semiconductor gap whose width is less than the semiconductor gap, the original single band can either split as in a Mott transition or not. The former situation is usual and almost always generalized. However the latter also takes place and results from a dilution effect of the self-interaction where a large orbital correlation is reduced if there are other orbital contributions with lower self-interaction in the band. The key is in the choice of the subspace of correlated orbitals. This effect can neither be ignored nor discarded for those systems where there is a substantial mix of states. Examples of these behaviors will be presented and compared to other results. Moreover, the combination of different Hubbard terms acting on different atomic state subspaces can also be used to correct the spurious self-interaction of the bands and the gap underestimation. The relationship between these terms applied to different subspaces of correlated electrons will be presented.

In the amphoteric membrane-less decoupled water electrolysis, hydrogen and oxygen are co-produced in separate cells with higher energy efficiency. Ion exchange is mediated by the auxiliary electrodes – HxWO3 for acid and NiOOH for alkaline cell.

The study evaluated the effect of environmental conditions and morphometric parameters on lake water temperature changes. The analysis was carried out on the basis of 14 lakes located in northern Poland. The assessment was based on the daily water and air temperatures from 1972 to 2016. It took into account the location of lakes (latitude, longitude, altitude) morphometric parameters (surface area, maximum and mean depth, volume), hydrological processes (rate of water exchange, course of ice phenomena), and trophic status (water transparency) as factors that can modify lake water temperature changes. Direction and rate of air and water temperature changes were analysed by means of Mann–Kendall’s and Sen’s tests. Cluster analysis (CA) was applied to group lakes characterised by similar water temperature changes. The effect of climatic and non-climatic parameters on a lake’s water temperature was assessed on the basis of principal component analysis (PCA). Water temperatures in the lakes in the years 1972–2016 were characterised by a higher rate of increase of 0.43 °C·dec−1 than the air temperature decrease of 0.34 °C·dec−1. The analysis showed a faster rate of heating of waters in western Poland. This can be explained by shorter duration of ice cover. Moreover, the changes of water temperature were affected by other factors, including the location of the lakes, their morphometric parameters, wind speed, water transparency and water exchange time.

This paper investigates key innovative paradigms that seek enhanced consensus building on the sustainable mining agenda of the mineral resource development industry and realities on the ground. It reviews the 55 most relevant academic articles from 2000 to 2019, retrieved from the Web of Science, PubMed and International Conference on Sustainable Development Indicators in the Metals Industry databases. A systematic scoping review method was used to sieve the multitudes of entries obtained from the databases to generate appropriate publications that match the search terms used. Our survey finds a dearth of literature on the subject. Only one article directly confers the need for consensus building on sustainable mining. The existing literature does not suggest the modalities that would enhance indigenous groups’ understanding and appreciation of sustainable mining. This creates a gap between stakeholders with regard to what flags sustainable mining. This study also finds a lack of efforts to incorporate sustainable mining concepts into academic courses focusing on either mining or sustainable development. Thus, this paper suggests that the existing delusions on sustainable mining can be addressed if the science of assessing and communicating the principles of sustainable development in mining is suitably developed and applied in higher educational curricula, environmental literacy feats, community-initiated research and outreach activities. Incorporating indigenous knowledge can address the existing gaps between stakeholder groups and in science.

Uncontaminated and As-contaminated fronds of Pteris vittata L., an As-hyperaccumulator fern used to phytoextract As from contaminated soils and water, were converted by sub-critical water (300 °C, 25 Pa) and supercritical water (400 °C, 25 Pa) treatments. Frond biomass was reduced between 70 and 77%. Compared to sub-critical conditions, supercritical conditions decreased C and inorganic contents in both the solid and liquid phases for uncontaminated and contaminated fronds and promoted CH4 formation. Higher As, Fe and Zn contents in contaminated fronds promoted decreasing C contents and the formations of cyclopentenones and benzenediols in the liquid phase. Al, Fe, P, Zn and Ca mainly remained in the solid phase whereas As and S were transferred to the liquid phase for both phytomasses. As the temperature increased from 300 °C to 400 °C, the concentrations of cyclopentenones and phenols in the liquid phase rose while those of guaiacols and other compounds decreased for both phytomasses. Arsenic in the liquid phase was removed by sorption on hydrous iron oxide.

The iminoborane (HBNH) molecule selectively breaks a B═N bond of smaller diameter single-wall BN nanotubes (BNNTs) and expands a ring at their surface, either at the edges or at the middle of the tube. Density functional theory is used to test whether its organic counterpart HCCH can do the same with BNNTs. HCCH–BNNT complexes are identified and transition states located for these combination reactions. Also explored are possible reactions of HBNH with single-wall carbon nanotubes (SWNTs) and HCCH with SWNTs. Data suggest that B═N (C═C) bond breaking, followed by ring expansion at the surface, may be possible. Although [2 + 2]cycloaddition reaction seems possible for HBNH–BNNTs, a high energy barrier hinders the process for other combinations of reactants. Introduction of substituents to HBNH/HCCH may allow a facile process. In most cases of HCCH–BNNTs, HBNH–SWNTs, and HCCH–SWNTs, transition states are identified and suggest an electron-rich reactant might lower barrier heights to form stable complexes. R...