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Abstract Given the fact that the solar industry is relatively mature, and the costs of equipment are stabilized, the utilization of solar thermal equipment in reducing the energy consumption in buildings increased. For this reason, in the frame of the present work, a new flat plate solar collector (H2OSS®) and a new solar air collector (Volet'air®) with high building integration were analyzed. Moreover, in concordance with the goals of European Project “Maritimo”, which implies refurbishing the Mediterranean houses, this Paper presents the energy reduction resulted from integrating these solar systems. They were used to refurbish a building placed in Bocognano, Corsica, France, near the center of the island. The performances of the patented solar equipment were simulated using the RETScreen software considering that the building has double utilization: two apartments are used for tourist accommodation (considered to be booked half a year), and two apartments serves as a church rectory (whole year utilization). Using the patented flat solar water collector, the annual energy requirement for hot water preparation decreased with 45%, from 2845 kWh to 1292 kWh, when analyzing the church rectory. Considering the same hot water consumption profile but using the vacuum solar collector, the total heat delivered increased to 1615 kWh, even if the total collector's area decreased from 2.02 m2 to 1.80 m2. The same vacuum system provided a 69% solar fraction (energy reduction from 1392 kWh/year to 960 kWh/year) for the accommodation apartments. The air heaters were mounded as windows shutters and have different areas for each orientation, thus different thermal energy production. Consequently, they were analyzed separately, and the heat delivered ranged from 646 kWh/year (East orientation) to 3479 kWh/year (South orientation). The total thermal energy provided by the solar air shutters was 5567 kWh/year, meaning approximatively 47% of the total energy required to maintain the interior temperature at 21 °C.

AbstractBlack locust (Robinia pseudoacacia L.), a species native to the eastern North America, was introduced to Europe probably in 1601 and currently extends over 2.3 × 106 ha. It has become naturalized in all sub-Mediterranean and temperate regions rivaling Populus spp. as the second most planted broadleaved tree species worldwide after Eucalyptus spp. This wide-spreading planting is because black locust is an important multipurpose species, producing wood, fodder, and a source of honey as well as bio-oil and biomass. It is also important for carbon sequestration, soil stabilization and re-vegetation of landfills, mining areas and wastelands, in biotherapy and landscaping. In Europe, black locust is drought tolerant so grows in areas with annual precipitation as low as 500–550 mm. It tolerates dry, nutrient poor soils but grows best on deep, nutrient-rich, well-drained soils. It is a fast-growing tree and the height, diameter and volume growth peak before the age of 20. It mostly regenerates vegetatively by root suckers under a simple coppice system, which is considered the most cost-effective management system. It also regenerates, but less frequently, by stool sprouts. Its early silviculture in production forests includes release cutting to promote root suckers rather than stool shoots, and cleaning-respacing to remove low-quality stems, reduce the number of shoots per stool, and adjust spacing between root suckers. In addition, early, moderate and frequent thinning as well as limited pruning are carried out focusing on crop trees. The species is regarded as invasive in several European countries and its range here is expected to expand under predicted climate changes.

Low coverage of urban and rural population to waste collection servicesleads to various environmental threats caused by uncontrolled wastedisposal. New EU regulations on waste management issues transposed intonational laws have improved this sector, but, the population access to suchservices is still low compared to others new EU members. A multi-scaleapproach of this indicator is a necessary tool for a proper analysis ofthis environmental issue. The maps reveal that Romanian development regions(NUTS 2) have the lowest coveragerates at EU level in 2010. Furthermore, major disparities are reflectedbetween Romanian counties in 2010. Thematic maps outline a comparativeanalysis at national and regional scale (Romanian counties & cities andcommunes of North-East Region) between urban vs rural areas in 2010. Thesegeographical approaches are necessary for a better monitoring process ofwaste management sector.

Abstract The non-absorption of photons with energies below the bandgap (Eg) and the thermalization of photons with energies higher than Eg are the dominant loss processes of single-junction solar cells. Rare earth doped glasses give the opportunity to convert the incident photons wavelength and hence to increase or decrease their energies. The conversion of photons energies by “up or down conversion” leads to the possibility to increase the efficiencies of all classes of single-junction solar cells. Depending on the nature of doping materials, two low energy photons can be converted into one high-energy photon (up-conversion), or one high energy photon, can be converted into two low energy photons (down-conversion). In this paper, Pr3+–Yb3+ down-conversion co-doped ZBLA glasses were tested as encapsulation materials for silicon solar cells. The J–V characterizations were done under solar simulator irradiation. The influence of Yb3+ concentration on the solar cells performances was investigated, showing that an optimum value between 0.5 and 2 mol% conducts to an increase of the device efficiency comparing to mono-doped ZBLA material.

Abstract It has been more than two decades since the discovery of nanofluids-mixtures of common liquids and solid nanoparticles less than 100 nm in size. As a type of colloidal suspension, nanofluids are typically employed as heat transfer fluids due to their favorable thermal and fluid properties. There have been numerous numerical studies of nanofluids in recent years (more than 1000 in both 2016 and 2017, based on Scopus statistics). Due to the small size and large numbers of nanoparticles that interact with the surrounding fluid in nanofluid flows, it has been a major challenge to capture both the macro-scale and the nano-scale effects of these systems without incurring extraordinarily high computational costs. To help understand the state of the art in modeling nanofluids and to discuss the challenges that remain in this field, the present article reviews the latest developments in modeling of nanofluid flows and heat transfer with an emphasis on 3D simulations. In part I, a brief overview of nanofluids (fabrication, applications, and their achievable thermo-physical properties) will be presented first. Next, various forces that exist in particulate flows such as drag, lift (Magnus and Saffman), Brownian, thermophoretic, van der Waals, and electrostatic double layer forces and their significance in nanofluid flows are discussed. Afterwards, the main models used to calculate the thermophysical properties of nanofluids are reviewed. This will be followed with the description of the main physical models presented for nanofluid flows and heat transfer, from single-phase to Eulerian and Lagrangian two-phase models. In part II, various computational fluid dynamics (CFD) techniques will be presented. Next, the latest studies on 3D simulation of nanofluid flow in various regimes and configurations are reviewed. The present review is expected to be helpful for researchers working on numerical simulation of nanofluids and also for scholars who work on experimental aspects of nanofluids to understand the underlying physical phenomena occurring during their experiments.

Earthworm distribution in global soils Earthworms are key components of soil ecological communities, performing vital functions in decomposition and nutrient cycling through ecosystems. Using data from more than 7000 sites, Phillips et al. developed global maps of the distribution of earthworm diversity, abundance, and biomass (see the Perspective by Fierer). The patterns differ from those typically found in aboveground taxa; there are peaks of diversity and abundance in the mid-latitude regions and peaks of biomass in the tropics. Climate variables strongly influence these patterns, and changes are likely to have cascading effects on other soil organisms and wider ecosystem functions. Science , this issue p. 480 ; see also p. 425