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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.

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.

Improper management of pig manure has resulted in environmental problems such as surface water eutrophication, ground water pollution, and greenhouse gas emissions. This study develops and compares 14 alternative manure management scenarios aiming at energy and nutrient extraction. The scenarios based on combinations of thermal pretreatment, anaerobic digestion, anaerobic co-digestion, liquid/solid separation, drying, incineration, and thermal gasification were compared with respect to their energy, nutrient and greenhouse gas balances. Both sole pig manure and pig manure mixed with other types of waste materials were considered. Data for the analyses were obtained from existing waste treatment facilities, experimental plants, laboratory measurements and literature. The assessment reveals that incineration combined with liquid/solid separation and drying of the solids is a promising management option yielding a high potential energy utilization rate and greenhouse gas savings. If maximum electricity production is desired, anaerobic digestion is advantageous as the biogas can be converted to electricity at high efficiency in a gas engine while allowing production of heat for operation of the digestion process. In conclusion, this study shows that the choice of technology has a strong influence on energy, nutrient and greenhouse gas balances. Thus, to get the most reliable results, it is important to consider the most representative (and up-to-date) technology combined with data representing the area or region in question.

Abstract Biogas production is one of the number of tools that may be used to alleviate the problems of global warming, energy security and waste management. Biogas plants can be difficult to sustain from a financial perspective. The facilities must be financially optimized through use of substrates with high biogas potential, low water content and low retention requirement. This research carried out in laboratory scale batch digesters assessed the biogas potential of energy crops (maize and grass silage) and solid manure fractions from manure separation units. The ultimate methane productivity in terms of volatile solids (VS) was determined as 330, 161, 230, 236, 361 L/kg VS from raw pig slurry, filter pressed manure fiber (FPMF), chemically precipitated manure fiber (CPMF), maize silage and grass silage respectively. Methane productivity based on mass (L/kg substrate) was significantly higher in FPMF (55 L/kg substrate), maize silage (68 L/kg substrate) and grass silage (45–124 L/kg substrate (depending on dry solids of feedstock)) as in comparison to raw pig slurry (10 L/kg substrate). The use of these materials as co-substrates with raw pig slurry will increase significantly the biomethane yield per unit feedstock in the biogas plant.

Earth’s biodiversity and human societies face pollution, overconsumption of natural resources, urbanization, demographic shifts, social and economic inequalities, and habitat loss, many of which are exacerbated by climate change. Here, we review links among climate, biodiversity, and society and develop a roadmap toward sustainability. These include limiting warming to 1.5°C and effectively conserving and restoring functional ecosystems on 30 to 50% of land, freshwater, and ocean “scapes.” We envision a mosaic of interconnected protected and shared spaces, including intensively used spaces, to strengthen self-sustaining biodiversity, the capacity of people and nature to adapt to and mitigate climate change, and nature’s contributions to people. Fostering interlinked human, ecosystem, and planetary health for a livable future urgently requires bold implementation of transformative policy interventions through interconnected institutions, governance, and social systems from local to global levels.

AbstractDonor–acceptor dyes are a well‐established class of photosensitizers, used to enhance visible‐light harvesting in solar cells and in direct photocatalytic reactions, such as H2 production by photoreforming of sacrificial electron donors (SEDs). Amines—typically triethanolamine (TEOA)—are commonly employed as SEDs in such reactions. Dye‐sensitized photoreforming of more sustainable, biomass‐derived alcohols, on the other hand, was only recently reported by using methanol as the electron donor. In this work, several rationally designed donor–acceptor dyes were used as sensitizers in H2 photocatalytic production, comparing the efficiency of TEOA and EtOH as SEDs. In particular, the effect of hydrophobic chains in the spacer and/or the donor unit of the dyes was systematically studied. The H2 production rates were higher when TEOA was used as SED, whereas the activity trends depended on the SED used. The best performance was obtained with TEOA by using a sensitizer with just one bulky hydrophobic moiety, propylenedioxythiophene, placed on the spacer unit. In the case of EtOH, the best‐performing sensitizers were the ones featuring a thiazolo[5,4‐d]thiazole internal unit, needed for enhancing light harvesting, and carrying alkyl chains on both the donor part and the spacer unit. The results are discussed in terms of reaction mechanism, interaction with the SED, and structural/electrochemical properties of the sensitizers.

AbstractThis paper presents a multiobjective optimization model to find efficient bus fleet combinations taking into account greenhouse gas emissions, conventional air pollutant emissions and costs...

AbstractThis study analyses the relationship between foreign direct investment, economic growth, urbanization, energy use, and carbon emissions in Brazil, Russia, India, China, and South Africa (BRICS countries) between 1990 and 2014. According to the empirical results, both environmental Kuznets curve (EKC) and pollution haven hypotheses (PHH) are confirmed. Urbanization contributes to reducing carbon emissions, while energy use is one of the main driving forces of ascending carbon emissions. The main advance of this paper lies in the moderating effect of foreign direct investment and energy usage on carbon emission in the case of the BRICS. The empirical results confirm a dampening impact of foreign direct investment on energy use, generating a correction in carbon emission. Thus, structural transformations are highlighted with a positive influence on energy efficiency and sustainable growth. It is expected that policymakers must promote renewable sources and boost clean foreign industries in selected host countries.

A very compact flat microbial fuel cell (MFC), with 64 cm2 each for the anode surface and the cathode surface and 1 cm3 each for the anode and cathode chambers, was tested for wastewater treatment with simultaneous electricity production with the ultimate goal of implementing an autonomous service in decentralized wastewater treatment systems. The MFC was operated with municipal wastewater in sequencing batch reactor mode with re-circulation. Current densities up to 407 W/m3 and a carbon removal of 83% were obtained. Interruption in the operation slightly decreased power density, while the re-circulation ratio did not influence power generation. The anode biofilm presented high conductivity, activity and diversity. The denaturing gradient gel electrophoresis band-pattern of the DNA showed the presence of several ribotypes with different species of Shewanellaceae and Geobacteraceae families.

The goal of developing ornamental landscapes that are safe, attractive, and functional for urban dwellers is pursued with great interest, and vast amounts of energy and material resources were used in this effort. However, direct and indirect energy consumption, the need for supplemental water, and the concerns about soil and ground water contamination raise serious questions regarding the long-term sustainability of urban landscapes. Sustainability in landscaping can be improved through a number of actions, such as planning and managing landscapes to function more like natural environments through cycling of resources and managing energy costs; integrating efforts to conserve water and energy, reduce green waste, improve soils, increase wildlife and reducing the demand for energy and material resources in other sectors of the urban environment through microclimate mitigation and habitat restoration. The objective of enviroscaping is to provide home gardeners and commercial landscapers with information that can help them to design and develop beautiful healthy, landscapes in an environmental friendly manner. The approach of enviroscaping is to manage landscapes as an interactive system by considering various components such as temperature, water/irrigation, fertilization, plants and trees, insect pest and pathogens control. Enviroscaping sets new dimension to landscape design and maintenance that can help us to conserve energy and water, recycle yard wastes on site and reduce inputs of fertilizers and pesticides into the environment.