Results 1 - 10 of 1994
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[en] The perspective by Haberl et al (2013 Environ. Res. Lett. 8 031004) entitled ‘Bioenergy: how much can we expect for 2050?’ is timely and valuable. It deals with an important subject since contrasting views on the subject make it very difficult for policy makers to adopt policies that would allow ‘production and consumption of energy at sustainable levels’, in the words of the authors. It is therefore very important to sort out from the abundant literature on the issue which are the facts and which are the biases and preferences. (perspective)
[en] Observations from the moderate resolution imaging spectroradiometer (MODIS) were used in combination with a large data set of field measurements to map woody above-ground biomass (AGB) across tropical Africa. We generated a best-quality cloud-free mosaic of MODIS satellite reflectance observations for the period 2000-2003 and used a regression tree model to predict AGB at 1 km resolution. Results based on a cross-validation approach show that the model explained 82% of the variance in AGB, with a root mean square error of 50.5 Mg ha-1 for a range of biomass between 0 and 454 Mg ha-1. Analysis of lidar metrics from the Geoscience Laser Altimetry System (GLAS), which are sensitive to vegetation structure, indicate that the model successfully captured the regional distribution of AGB. The results showed a strong positive correlation (R2 = 0.90) between the GLAS height metrics and predicted AGB.
[en] There is a need to understand the carbon (C) sequestration potential of the forestry option and its financial implications for each country. In India the C emissions from deforestation are estimated to be nearly offset by C sequestration in forests under succession and tree plantations. India has nearly succeeded in stabilizing the area under forests and has adequate forest conservation strategies. Biomass demands for softwood, hardwood and firewood are estimated to double or treble by the year 2020. A set of forestry options were developed to meet the projected biomass needs, and keeping in mind the features of land categories available, three scenarios were developed: potential; demand-driven; and programme-driven scenarios. Adoption of the demand-driven scenario, targeted at meeting the projected biomass needs, is estimated to sequester 78 Mt of C annually after accounting for all emissions resulting from clearfelling and end use of biomass. The demand-driven scenario is estimated to offset 50% of national C emission at 1990 level. The cost per t of C sequestered for forestry options is lower than the energy options considered. The annual investment required for implementing the demand-driven scenario is estimated to be US$ 2.1 billion for six years and is shown to be feasible. Among forestry options, the ranking based on investment cost per t of C sequestered from least cost to highest cost is; natural regeneration -agro-forestry-enhanced natural regeneration ( < US$ 2.5/t C) -timber-community-forestry (US$ 3.3 to 7.3 per t of C). (Author)
[en] Cellulose-paper sludges belong to decisive group of technological wastes of organic origin in cellulose-paper industry. Evaluation of the wastes with respect on attainment of positive environmental impact is the key to attainment of required environmental productivity of enterprise. In the present time the most effective ways of evaluation of cellulose-paper sludges is the evaluation in the industry of construction materials, what can be considered like energetic evaluation of the wastes and in production of composts and fertilizer substrates. Energetic evaluation of cellulose-paper muds by direct combustion is only little theoretically examined and tested in practice for the present. Environmental impact of evaluation of the wastes in this way is necessary to evaluate environmentally comprehensively. (author)
[en] Bioinspired design approaches seek to exploit nature in order to construct optimal solutions for engineering problems as uniform temperature control in multizone systems. The ideal free distribution (IFD) is a concept from behavioural ecology, which describes the arrangement of individuals in different habitats such that at equilibrium, all habitats are equally suitable. Here, we relax the IFD's main assumptions using the standing-crop idea to introduce dynamics into the supplies of each habitat. Then, we make an analogy with a multizone thermal system to propose a controller based on the replicator dynamics model, in order to obtain a maximum uniform temperature subject to constant power injection. Besides, we analytically show that the equilibrium point of the controlled system is asymptotically stable. Finally, some practical results obtained with a testbed and comparisons with the theoretical results are presented.
[en] Land application of organic wastes to short rotation woody crops (SRWC) can reduce the environmental impacts associated with waste disposal and enhance the productivity of biomass production systems. Understanding the potential impacts of organic amendments however, requires the examination of changes in soil characteristics and plant productivity. This study was conducted to evaluate the effect of paper sludge and dairy manure on biomass production of shrub willow (Salix dasyclados SV1) and to determine the impacts of these amendments on soil chemical properties. Treatments included urea, dairy manure and paper sludge separately and in combination, and a control. These materials were applied in the summer of 2005 to two fields of SV1 at different stages of growth: An old field with one year old shoots on a 10 year old root system and a young field which was beginning regrowth after being coppiced at the end of its first growing season. Foliar nutrient concentrations and soil chemical properties were analyzed at the end of the second growing season after treatment application to determine plant response to the fertilization regimes and to determine the effects of fertilization on soil characteristics. Fertilization did not increase biomass production in either field. However, application of the N-poor paper sludge did not reduce yield either. In general, fertilization did not influence soil or foliar chemistry, although there were some exceptions. The lack of response observed in this study is probably related to the nutrient status of the site or losses of applied nutrients. -- Highlights: → The fertilization treatments did not have any significant effect biomass production. → Application of paper sludge did not reduce willow biomass yield in both fields. → Foliar N concentration of willow crops in this study is in the range considered for optimal growth. → The limited response of foliar nutrients to fertilization indicates that the site was not limited by nutrient availability. → Organic amendments did not have any significant effect on total soil N.
[en] Forest-fragmentation-related edge effects are one of the major causes of forest degradation in Amazonia and their spatio-temporal dynamics are highly influenced by annual deforestation patterns. Rapid biomass collapse due to edge effects in forest fragments has been reported in the Brazilian Amazon; however the collective impacts of this process on Amazonian carbon fluxes are poorly understood. We estimated biomass loss and carbon emissions from deforestation and forest fragmentation related to edge effects on the basis of the INPE (Brazilian National Space Research Institute) PRODES deforestation data and forest biomass volume data. The areas and ages of edge forests were calculated annually and the corresponding biomass loss and carbon emissions from these forest edges were estimated using published rates of biomass decay and decomposition corresponding to the areas and ages of edge forests. Our analysis estimated carbon fluxes from deforestation (4195 Tg C) and edge forest (126-221 Tg C) for 2001-10 in the Brazilian Amazon. The impacts of varying rates of deforestation on regional forest fragmentation and carbon fluxes were also investigated, with the focus on two periods: 2001-5 (high deforestation rates) and 2006-10 (low deforestation rates). Edge-released carbon accounted for 2.6-4.5% of deforestation-related carbon emissions. However, the relative importance of carbon emissions from forest fragmentation increased from 1.7-3.0% to 3.3-5.6% of the respective deforestation emissions between the two contrasting deforestation rates. Edge-related carbon fluxes are of increasing importance for basin-wide carbon accounting, especially as regards ongoing reducing emissions from deforestation and forest degradation (REDD) efforts in Brazilian Amazonia.
[en] The fast pyrolysis of empty fruit bunches (EFB) was carried out using a fluidized-fixed bed reactor. An electric furnace heated the reactor with a heated length of 135 mm and an inner diameter of 40 mm. The sand bed was fluidized using argon at a rate of 0.5 litre per minute (LPM). The sand bed consisted of 100 g zircon sand of 180 - 250 μm. Several process parameters such as the pyrolysis temperature, particle size and different types of pre-treatment that can affect the yield of the pyrolysis products were investigated. The experiment of fast pyrolysis was conducted using 2 - 4 g of EFB which was fed into the reactor using argon at a rate of 2.5 LPM. The temperature used was in the range of 400-600 degree Celsius and particle size of EFB was < 90 - 150 μm. Three types of pre-treatment were performed i.e. washing EFB with H2SO4, NaOH and distilled water. The results indicated that the optimum yield of bio-oils was obtained using unwashed EFB having particle size of 91-106 μm at pyrolyzed temperature of 500 degree Celsius. The maximum yield of bio-char was obtained using washed EFB with NaOH at temperature of 600 degree Celsius and particle size of 106-125 μm. (author)