Experimental and theoretical investigation of diffusion processes in a membrane anaerobic reactor for bio-hydrogen production

This paper explores the potential for advanced membranes to act as a sink for hydrogen generated during anaerobic digestion thereby maintaining very low hydrogen concentrations and more favorable conditions for fermentative and possibly acetate oxidative pathways. This necessitates that the membranes function when submerged in water.     

Analysis of directional factors in milling: importance of multi-frequency calculation and of the inclusion of the effect of the helix angle

The concept of directional factor for chatter stability analysis has been used from a long time ago. The analysis of its evolution for different feed directions in milling processes provides a good way of selecting the best cutting conditions. For very stable cutting directions, corresponding to very low directional factors, the single frequency analysis gives unacceptable results and multi-frequency, or alternative solutions as semi-discretisation must be used. It is found also that the period doubling lobes extend at both sides of the tooth pass frequency equivalent to twice the natural frequency. In these cases, helix angle has a very important effect on the stability. For end milling processes, where the mill axial pitch can be of the order of the stable limit depth of cut, a very stable situation is found except in those areas corresponding to period doubling, where instability islands are found. Besides, a graphical construction for accurate estimation of the stable limit depth of cut and starting rotational speed of the period doubling lobes is proposed.     

Assessing the Integration of Landscape Connectivity into Comprehensive Spatial Planning in Spain

The integration of landscape connectivity criteria into spatial planning through ecological networks formed by coherent open space systems has received increasing attention in Europe in the last few decades. In Spain, such integration began recently, in parallel with the development of a supralocal comprehensive spatial planning policy, which was practically non-existent a decade ago. An assessment of such integration is reported here, specifically on ecological networks inclusion within the spatially explicit zoning regulations of 11 regional and 66 subregional plans which had been approved in Spain until the end of 2012. At the same time, a survey was conducted among 22 Spanish and 14 European practitioners in order to detect possible deficiencies and opportunities to optimise this integration in Spain through a comparison with other European countries. An increasing integration of ecological networks into supralocal plans was observed, especially in subregional plans approved in the last five years, coinciding with a period of greater development in supralocal spatial planning policy, the end of the Spanish speculative housing bubble and new national legislation which encourages the promotion of ecological networks. However, the integration process is very uneven because homogeneous guidelines are not applied in the different regions. Spanish practitioners discerned wide room for improvement. The integration of ecological networks into multiscale spatial planning should be optimised in Spain, including improvements in local planning, strategic environmental assessment and training of planners in this topic.     

Natural variation of toxicity in encrusting spongeCrambe crambe (Schmidt) in relation to size and environment

The presence of intraspecific variation in toxicity and its relationship with biological or ecological factors were studied in the spongeCrambe crambe. Within-specimen (periphery and central part), between-size (<1000 mm² in area, between 1000 and 10,000 mm² and >10,000 mm²) and between-habitat (well-illuminated and dark communities) variations in toxicity were evaluated by the Microtox bioassay. Quantitative differences were detected that were not attributable to within-specimen variation but to size and habitat effects. Habitat comparisons showed that sponges in the shaded habitat were significantly more toxic than those of the well-illuminated community. Sponges of the smaller size classes displayed significantly less toxicity than the medium-sized specimens. Results are interpreted under the optimal defense theory and their ecological implications are considered.     

Performance assessment of membrane distillation for skim milk and whey processing

Membrane distillation is an emerging membrane process based on evaporation of a volatile solvent. One of its often stated advantages is the low flux sensitivity toward concentration of the processed fluid, in contrast to reverse osmosis. In the present paper, we looked at 2 high-solids applications of the dairy industry: skim milk and whey. Performance was assessed under various hydrodynamic conditions to investigate the feasibility of fouling mitigation by changing the operating parameters and to compare performance to widespread membrane filtration processes. Whereas filtration processes are hydraulic pressure driven, membrane distillation uses vapor pressure from heat to drive separation and, therefore, operating parameters have a different bearing on the process. Experimental and calculated results identified factors influencing heat and mass transfer under various operating conditions using polytetrafluoroethylene flat-sheet membranes. Linear velocity was found to influence performance during skim milk processing but not during whey processing. Lower feed and higher permeate temperature was found to reduce fouling in the processing of both dairy solutions. Concentration of skim milk and whey by membrane distillation has potential, as it showed high rejection (>99%) of all dairy components and can operate using low electrical energy and pressures (<10 kPa). At higher cross-flow velocities (around 0.141 m/s), fluxes were comparable to those found with reverse osmosis, achieving a sustainable flux of approximately 12 kg/h·m² for skim milk of 20% dry matter concentration and approximately 20 kg/h·m² after 18 h of operation with whey at 20% dry matter concentration.     

Territorial innovation models: to be or not to be,that’s the question

Scientometrics - In a recent paper, Hirsch (hα: an index to quantify an individual’s scientific leadership, 2019. https://doi.org/10.1007/s11192-018-2994-1 )&nbsp; proposes to...