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Wood biomass is turned into industrial fuel through chipping. The efficiency of chipping depends on many factors, including chipper knife wear. Chipper knife wear was determined through a long-term follow-up study, conducted at a waste wood recycling yard. Knife wear determined a sharp drop of productivity (>20%) and a severe decay in product quality. Dry sharpening with a grinder mitigated this effect, but it could not replace proper wet sharpening. Increasing the frequency of wet sharpening sessions determined a moderate increase of knife depreciation cost, but it could drastically enhance machine performance and reduce biomass processing cost. Since benefits largely exceed costs, increasing the frequency of wet sharpening sessions may be an effective measure for reducing overall chipping cost. If the main goal of a chipper operator is to increase productivity and/or decrease fuel consumption, then managing knife wear should be a primary target. (C) 2014 Elsevier Ltd. All rights reserved.

Wet-laying is a mature technology that is applied in large scale for the manufacture of nonwovens, including paper products. However, it usually uses large volumes of water and is energy-intensive. Here we used foam-laying to substantially diminish the volume of water consumed in the formation of fiber networks (5-fold reduction) and to reduce the water content of the nonwovens produced before drying, achieving a reduced energy demand. The prospects of foam-laying were evaluated by comparing foam-laid and wet-laid webs of two types of wood fibers: stiff (lignin-containing) or flexible (lignin-free). Also, the effect of foaming agent type (anionic, cationic, nonionic, and amphoteric) was elucidated. Reference webs were produced by conventional wet-laying, with or without surfactants. Foam-laying was effective in producing a more uniform areal mass distribution (better formation) after wet-pressing. This effect was more evident for the webs synthesized with the flexible fibers. Unlike the layered network structures that were obtained by wet-laying, foam-laid webs exhibited a more felted network, with fibers positioned in the out-of-plane direction. As a result, higher air permeability, web porosity, and light scattering coefficients were measured for the foam-laid webs. The enhanced porosity (lower density) was related to the effect of bubbles during foam-laying and the reduction in surface tension of the foamed-fiber dispersion. The resistance to delamination of low-density webs obtained by foam-laying in the out-of-plane direction was preserved. However, the reduction in tensile strength and modulus of foam-laid webs were determined, owing to the reduced density of the formed structures. Notably, the type of foaming agent used played a minor role as far as the resultant properties of the webs, making the process flexible in terms of the selection of environmentally friendly alternatives. Overall, we compared the physico-mechanical properties of fiber networks formed by web- and foam-laying, depending on fiber type and foaming agent, yielding a property space that is useful in the design of lightweight structures (nonwovens, including paper). The prospects of water and energy savings by foam-laying are the major benefits in the sustainable use of fibers for the assembly of porous materials, such as lightweight nonwoven and paper products.

Abstract Electrolyte-separator-free fuel cell (EFFC) is a new emerging energy conversion technology. The EFFC consists of a single-component of nanocomposite material which works as a one-layer fuel cell device contrary to the traditional three-layer anode–electrolyte–cathode structure, in which an electrolyte layer plays a critical role. The nanocomposite of a single homogenous layer consists of a mixture of semiconducting and ionic materials that provides the necessary electrochemical reaction sites and charge transport paths for a fuel cell. These can be accomplished through tailoring ionic and electronic (n, p) conductivities and catalyst activities, which enable redox reactions to occur on nano-particles and finally accomplish a fuel cell function.

The repercussions of climate change will be felt in various ways throughout both natural and human systems in Sub-Saharan Africa. Climate change projections for this region point to a warming trend, particularly in the inland subtropics; frequent occurrence of extreme heat events; increasing aridity; and changes in rainfall—with a particularly pronounced decline in southern Africa and an increase in East Africa. The region could also experience as much as one meter of sea-level rise by the end of this century under a 4 °C warming scenario. Sub-Saharan Africa’s already high rates of undernutrition and infectious disease can be expected to increase compared to a scenario without climate change. Particularly vulnerable to these climatic changes are the rainfed agricultural systems on which the livelihoods of a large proportion of the region’s population currently depend. As agricultural livelihoods become more precarious, the rate of rural–urban migration may be expected to grow, adding to the already significant urbanization trend in the region. The movement of people into informal settlements may expose them to a variety of risks different but no less serious than those faced in their place of origin, including outbreaks of infectious disease, flash flooding and food price increases. Impacts across sectors are likely to amplify the overall effect but remain little understood.

This paper serves as an introduction to this special issue on new developments in urban transportation planning. The papers in this issue highlight how physical mobility is still an essential priority for urban life, but that there are associated costs in the terms of environmental impacts, quality of life and economic performance of cities. Four features of the emerging urban transportation field are identified. The first defining feature is that it is a discipline in the midst of a paradigmatic transition. Second is its overarching aim of achieving sustainable urban mobility as part of a broader effort towards enhancing quality of life in cities. The third feature is the emphasis on collaboration, integration and exchange with other professions and policy sectors. The last distinctive feature is the recognition that urban transportation planning is a communication-oriented activity.

Abstract Hydrothermal liquefaction (HTL) is a promising technology for converting organic-rich waste biomass such as swine manure (SM) and sewage sludge (SS) into energy-dense bio-crude. Until now, one of the major challenges associated with HTL is the pumpability of high dry-matter containing fibrous feedstocks for continuous processing. In this context, this batch scale study presents a suitable approach for enhancing the pumpability of the fibrous material, specifically SM, by co-processing with SS. Obtained results showed that SM was not pumpable itself due to its fibrous nature, but became pumpable by the addition of SS at overall 25 % dry matter content. It was highlighted that the sample mixture containing ~80 % of the SM was smoothly pumped with 20 % SS. Subsequently, HTL experiments were carried out on samples mixed under the ratios SM:SS (100:0, 0:100, 50:50, 80:20, and 20:80). The highest bio-crude yield (42.38 %) via maximum synergistic effect was obtained from the sample SM/SS (50:50) at ratio 1:1 with the best HHV of 36 MJ/kg. Almost 60–70 % mass of all bio-crudes contained volatiles at 350 °C. ICP-AES measurements revealed that the majority of the inorganic elements were concentrated into the solid phase, while 40–50 % of the potassium and sodium were transferred to the aqueous phase. In conclusion, using SS as a co-substrate with SM not only enhances the pumpability of SM, but its co-liquefaction has demonstrated beneficial synergistic effects on improving the energy recovery of the bio-crude.

Forest biomass is one of the main contributors to the EU's renewable energy target of 20% gross final energy consumption in 2020 (Renewable Energy Directive). Following the RED, new sustainability principles are launched by the European energy sector, such as the Initiative Wood Pellet Buyers (IWPB or SBP). The aim of our study is the investigation of the quantitative impacts from IWPB's principles for forest biomass for energy only. We deploy a bottom up method that quantifies the supplies and the costs from log harvest until forest chip delivery at a domestic consumer. We have a reference situation with existing national (forest) legislation and voluntary certification schemes (scenario 1) and a future situation with additional criteria based on the IWPB principles (scenario 2). Two country studies were selected for our (2008) survey: one in Finland with nearly 100% certification and one in Leningrad province with a minor areal share of certification in scenario 1. The sustainable potential of forest resources for energy is about 54 Mm3 (385 PJ) in Finland and about 13.5 Mm3 (95 PJ) in Leningrad in scenario 1 without extra criteria. The potential volumes reduce considerably by maximum 43% respectively 39% after new criteria from the IWPB, like a minimum use of sawlogs, stumps and slash for energy, and by an increased area of protected forests (scenario 2A Maximum extra restrictions). In case sawlogs can be used, but instead ash recycling is applied after a maximum stump and slash recovery (scenario 2B Minimum extra restrictions), the potential supply is less reduced: 5% in Finland and 22% in Leningrad region. The estimated reference costs for forest chips are between €18 and €45 solid m-3 in Finland and between €7 and €33 solid m-3 in the Leningrad region. In scenario 2A, the costs will mainly increase by €7 m-3 for delimbing full trees (Finland), and maximum €0.3 m-3 for suggested improved forest management (Leningrad region). In scenario 2B, when ash recycling is applied, costs increase by about €0.3 to €1.6 m-3, depending on the rate of soil contamination. This is an increase of 2%, on top of the costs in scenario 2A.

In our previous studies on the intestinal microbiota in irritable bowel syndrome (IBS), we identified a bacterial phylotype with higher abundance in patients suffering from diarrhea than in healthy controls. In the present work, we have isolated in pure culture strain RT94, belonging to this phylotype, determined its whole genome sequence and performed an extensive genomic analysis and phenotypical testing. This revealed strain RT94 to be a strict anaerobe apparently belonging to a novel species with only 94% similarity in the 16S rRNA gene sequence to the closest relatives Ruminococcus torques and Ruminococcus lactaris. The G + C content of strain RT94 is 45.2 mol% and the major long-chain cellular fatty acids are C16:0, C18:0 and C14:0. The isolate is metabolically versatile but not a mucus or cellulose utilizer. It produces acetate, ethanol, succinate, lactate and formate, but very little butyrate, as end products of glucose metabolism. The mechanisms underlying the association of strain RT94 with diarrhea-type IBS are discussed.