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Gebbers R.,Leibniz Institute for Agricultural Engineering | Adamchuk V.I.,University of Nebraska - Lincoln
Science | Year: 2010

Precision agriculture comprises a set of technologies that combines sensors, information systems, enhanced machinery, and informed management to optimize production by accounting for variability and uncertainties within agricultural systems. Adapting production inputs site-specifically within a field and individually for each animal allows better use of resources to maintain the quality of the environment while improving the sustainability of the food supply. Precision agriculture provides a means to monitor the food production chain and manage both the quantity and quality of agricultural produce. © 2010 American Association for the Advancement for Science. All Rights Reserved. Source


The characterization of cellulase performance for industrial-scale processes holds special challenges. A huge gap exists between the enzyme characterization in a laboratory and large-scale process performances. Common cellulase mixtures from Novozymes and enzymes provided by Moscow State University were used to hydrolyze wheat straw, grass, pine wood, and aspen wood. Glucose yields from the enzymatic hydrolysis of the raw materials were investigated as a function of cellulase enzyme loading and of particle sizes with different solid loading. The particle size had a significant effect on glucose yield, while the used enzyme concentration had a much smaller effect. Hydrolyses of sets of wheat straw particles were used to introduce a substrate-specific kinetic enzyme unit. The data were also used to generate an empirical model in order to predict the glucose yield on the basis of the Sauter mean diameter of the feedstocks. © 2015. Source


Kruse A.,Karlsruhe Institute of Technology | Kruse A.,University of Hohenheim | Funke A.,Leibniz Institute for Agricultural Engineering | Titirici M.-M.,Queen Mary, University of London
Current Opinion in Chemical Biology | Year: 2013

Available biomass, preferentially residues, can be divided in two groups: biomass with a high or natural water content ('wet' or 'green' biomass) and biomass with low water content such as wood and straw. In 'dry' biomass gasification processes, originating in most coal processing technologies, biomass of low water content is necessary to avoid the energy loss by water evaporation. In contrast, hydrothermal processes need water as reaction medium; therefore, these processes are preferentially used for wet or 'green' biomass.In this review paper we will describe the main research directions in the hydrothermal conversion of biomass into fuels and carbon throughout gasification to produce H2 or CH4, liquefaction to produce crude oils and phenols from lignin as well as carbonization to produce carbonaceous materials which can be either used as fuels (carbon negative chars) or interesting energetic materials (hydrothermal carbons). © 2013 Elsevier Ltd. Source


Zdunek A.,Polish Academy of Sciences | Herppich W.B.,Leibniz Institute for Agricultural Engineering
Postharvest Biology and Technology | Year: 2012

Biospeckle is a relatively new and potentially valuable method for non-invasive evaluation of quality of fresh fruits and vegetables. It has been proposed that biospeckle reflects particle movement at the cellular or sub-cellular level. However, the biological bases for the correct interpretation of this phenomenon, as well as the data obtained with this approach, are still rarely investigated. For studying biospeckle activity, normally red lasers are used. On the other hand, this wavelength is absorbed by chlorophyll. Hence, light propagation and biospeckle activity could be affected by the presence of this photosynthetic pigment. The goal of this study was to evaluate the potential interrelationships between the biospeckle activity and chlorophyll content in apples. The experiment showed that, for apples, the biospeckle activity linearly decreases with increasing chlorophyll content. Low coefficients of determination (R2∼0.3) suggest that the real movement of particles, reflected by biospeckle, is masked by light absorption. © 2011 Elsevier B.V. Source


Germer S.,Leibniz Institute for Agricultural Engineering
Journal of Hydrology | Year: 2013

Rainfall falling on canopies is redistributed and reaches the soil surface as throughfall or stemflow. I investigate stemflow generation by babassu palms (Attalea speciosa Mart.) in a Brazilian agroforestry system and its fate once the stemflow water reached the soil surface. Rainfall, stemflow and perched water tables were monitored on rainfall-event basis. Dye tracer experiments monitored stemflow-induced preferential flow paths. Root distributions were related to soil water redistribution. Perched water tables and roots were studied only on adult palms, while stemflow measurements and dye tracer experiments were performed on young palms, too. Average rainfall-collecting area per adult palm was 6.4±0.3m2 (±SE). Funneling ratios (ratio of stemflow volume and basal area normalized by rainfall depth) ranged between 16-71 and 4-55 for adult and young palms, respectively. On average, 9.1±3.1L (±SE) of adult palm stemflow were intercepted. For adult palms, stemflow induced soil saturation and, hence, perched water tables were detected more frequently near adult palm stems than further away. Tracer experiments at adult palms revealed initial preferential horizontal flow, with subsequent downward water movement towards the lower wetting front. Meanwhile, young palms funneled rainfall via their fronds directly to their subterranean stems. Coarse roots density of adult palms was highest next to the subterranean stem and, consequently, palms might profit from increased water input compared to open area rainfall. Beside this positive effect for this very abundant palm species in Brazil, the generation of soil saturation next to the palm stems might also lead to negative environmental impacts. As discussed soil saturation and simultaneous input of nitrate and presumably dissolved organic carbon could lead to hotspots of denitrification and, hence, greenhouse gas emissions. © 2013 Elsevier B.V. Source

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