| 1. |
- Hamid Muhammed, Hamed, et al.
(author)
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Feature vector based analysis of hyperspectral crop reflectance data for discrimination and quantification of fungal disease severity in wheat
- 2003
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In: Biosystems Engineering. - 1537-5110 .- 1537-5129. ; 86:2, s. 125-134
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Journal article (peer-reviewed)abstract
- The impact of plant pathological stress on crop reflectance can be measured both in broad-band vegetation indices and in narrow or local characteristics of the reflectance spectra. This work is concerned with using the whole spectra in the objective examination of how different parts of the spectrum contribute in describing disease severity in wheat. A hyperspectral reflectance spectrum was considered as a mixed signal, i.e. the integration of the effects of all active objects in the investigated area. Independent component analysis (ICA) was used to blindly separate mixed statistically independent signals. Principal component analysis (PCA) was also used to extract interesting components. The ICA or PCA results had then to be interpreted efficiently. This was achieved by using a technique called feature-vector-based analysis (FVBA), which produces a number of 'component-feature vector' pairs, which represent the spectral signatures and the corresponding weighting coefficients of the different constituting source signals. These weighting coefficients were proportional to field assessments of fungal disease severity in a spring wheat crop, in percentage necrosis of leaf area, and high correlations were shown. Two effects of increased disease severity were observed: (1) a flattening of the green reflectance peak together with a general decrease in reflectance in the near-infrared region and (2) a decrease of the shoulder of the near-infrared reflectance plateau together with a general increase in the visible region between 550 and 750 nm.
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| 2. |
- Ahlgren, S., et al.
(author)
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Future fuel supply systems for organic production based on Fischer-Tropsch diesel and dimethyl ether from on-farm-grown biomass
- 2008
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 99:1, s. 145-155
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Journal article (peer-reviewed)abstract
- The effects of making a 1000 ha organic farm self-sufficient in renewable fuel were studied. Biomass grown on-farm can be transported to large fuel production facilities and the fuel transported back to the farm. Two fuels, Fischer-Tropsch diesel (FTD) and dimethyl ether (DME), produced from either straw or short-rotation willow coppice (Salix), were studied. The environmental impact, land use and energy balance were calculated using life-cycle methodology. It was calculated that the straw-based systems had only 32-39% of the impact on global warming (kg [CO2-eq]) compared to the Salix-based systems. For acidification and eutrophication, the differences between the systems were less significant. The energy balances were 8.9 and 9.6 for FTD and 10.1 and 10.0 for DME, from straw and Salix, respectively. To become self-sufficient in FTD, 108 ha has to be set aside for Salix production or 261 ha of straw collected from the existing crop rotation. For DME the corresponding figures are 38 and 70 ha. The many by-products in the FTD scenarios explain the large difference between fuels. Comparing FTD and DME, the differences in environmental impact were small. Considering this, FTD is a more likely alternative since DME requires a pressurised infrastructure system and engine modifications. © 2007 IAgrE.
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| 3. |
- Andersson, Karin, et al.
(author)
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Ammonia emissions from untreated, separated and digested cattle slurry-Effects of slurry type and application strategy on a Swedish clay soil
- 2023
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 226, s. 194-208
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Journal article (peer-reviewed)abstract
- Animal slurry contains plant nutrients such as nitrogen (N) that are essential for crop production. Inorganic slurry N is easily volatilised as ammonia after field application, reducing slurry fertiliser value and causing environmental problems. Ammonia emissions can be reduced by lowering slurry pH, rapid infiltration or incorporation of slurry into soil. This study investigated the effect of different combinations of slurry types and application strategies on ammonia emissions. The slurry types tested were untreated cattle slurry (CS), the liquid fraction from mechanical solid-liquid separation of cattle slurry (LF) and biogas digestate based mainly on cattle slurry (BD). The application strategies tested were trailing hoses, trailing shoes, trailing hose application of acidified slurry and slurry injection. Ammonia emissions after slurry application were measured using wind tunnels, with continuous measurements of ammonia concentrations in outgoing air. Comparisons were also made between measured ammonia emissions and emissions predicted by the ALFAM2 model. Cumulative ammonia emissions after 70 h from LF, CS and BD represented 23%, 29% and 32% of total ammoniacal nitrogen (TAN) applied. Trailing shoes and 50 mm deep injection slots reduced ammonia emissions by on average 17% and 37%, respectively, compared with trailing hoses. Slurry acidification resulted in an average reduction in ammonia emissions of 83%. The ALFAM2 model was reasonably accurate in predicting cumulative emissions (70 h). Accuracy in predicting emission dynamics was low in some cases, likely due to differences between wind tunnel measurements and open-air emis-sions and to model error.(c) 2023 The Authors. Published by Elsevier Ltd on behalf of IAgrE. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 4. |
- Andersson, Karin, et al.
(author)
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Effect of exposed surface area on ammonia emissions from untreated, separated, and digested cattle manure
- 2021
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 202, s. 66-78
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Journal article (peer-reviewed)abstract
- Ammonia (NH3) emissions from land-applied liquid manure (slurry) contribute to nitrogen deposition, acidification, and formation of fine particles in the atmosphere. Optimal management and field application techniques can reduce emission. A reduction in contact area between the slurry and the atmosphere is expected to reduce NH3 emission. The objectives of this study were to develop a method for quantifying the exposed surface area (ESA) of field-applied slurry over time, and determine the degree to which ESA explains differences in NH3 emission. Two experiments were conducted in which untreated, separated, and digested slurry was applied in bands on two different soils with spring oats stubble. Emission data were obtained from online wind tunnel measurements and slurry characteristics such as surface pH, viscosity, and particle size distribution were measured. The new ESA method relies on fluorescent dye added to the slurry prior to field application, followed by imaging. The results show that the ESA measurements can give new insight into the soil-slurry interactions after manure application, and this may help explain why some types of slurry and application techniques lead to successful abatement under some circumstances, but not under others. Furthermore, a pH-, TAN-, temperature-, and ESA normalised NH3 emission were estimated, helping idetify the effects of infiltration. (c) 2020 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 5. |
- Chelotti, J. O., et al.
(author)
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Livestock feeding behaviour : A review on automated systems for ruminant monitoring
- 2024
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 246, s. 150-177
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Research review (peer-reviewed)abstract
- Livestock feeding behaviour is an influential research area in animal husbandry and agriculture. In recent years, there has been a growing interest in automated systems for monitoring the behaviour of ruminants. Current automated monitoring systems mainly use motion, acoustic, pressure and image sensors to collect and analyse patterns related to ingestive behaviour, foraging activities and daily intake. The performance evaluation of existing methods is a complex task and direct comparisons between studies is difficult. Several factors prevent a direct comparison, starting from the diversity of data and performance metrics used in the experiments. This review on the analysis of the feeding behaviour of ruminants emphasise the relationship between sensing methodologies, signal processing, and computational intelligence methods. It assesses the main sensing methodologies and the main techniques to analyse the signals associated with feeding behaviour, evaluating their use in different settings and situations. It also highlights the potential of the valuable information provided by automated monitoring systems to expand knowledge in the field, positively impacting production systems and research. The paper closes by discussing future engineering challenges and opportunities in livestock feeding behaviour monitoring.
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| 6. |
- Das, Atanu Kumar, et al.
(author)
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Investigating the influence of work piece geometry on the specific energy use in size reduction with a multi-blade shaft mill
- 2021
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 209, s. 210-215
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Journal article (peer-reviewed)abstract
- This study investigated the specific milling energy of rectangular pine (Pinus sylvestris L.) boards using a new size reduction technology, which can produce fine wood powders in a single-step operation. Multilinear regression (MLR) analysis was used to model the milling energy of a multi-blade shaft mill through a designed series of experiments having three input parameters: the moisture content of the board, milling blade speed and board feeding speed. The observed specific milling energy ranged from 60 to 172 kWh t−1 [DM] and the MLR model showed it was proportional to the blade speed and the moisture content. The results suggest that multi-blade shaft milling is a two-dimension extension of singular circular blade milling with regard to work piece shape and sawblade teeth engagement effects. The findings were compared with the specific milling energy of pine logs obtained in a previous study.
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| 7. |
- Das, Atanu Kumar, et al.
(author)
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Investigating the influence of work piece geometry on the specific energy use in size reduction with a multi-blade shaft mill
- 2021
-
In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 209, s. 210-215
-
Journal article (peer-reviewed)abstract
- This study investigated the specific milling energy of rectangular pine (Pinus sylvestris L.) boards using a new size reduction technology, which can produce fine wood powders in a single-step operation. Multilinear regression (MLR) analysis was used to model the milling energy of a multi-blade shaft mill through a designed series of experiments having three input parameters: the moisture content of the board, milling blade speed and board feeding speed. The observed specific milling energy ranged from 60 to 172 kWh t−1 [DM] and the MLR model showed it was proportional to the blade speed and the moisture content. The results suggest that multi-blade shaft milling is a two-dimension extension of singular circular blade milling with regard to work piece shape and sawblade teeth engagement effects. The findings were compared with the specific milling energy of pine logs obtained in a previous study.
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| 8. |
- De Bruijn, Paulien, et al.
(author)
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Mechanical properties of lime-hemp concrete containing shives and fibres
- 2009
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 103:4, s. 474-479
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Journal article (peer-reviewed)abstract
- The effect of using different binding agents in combination with hemp shives and fibres in Lime-Hemp Concrete (LHC) building material was examined. LHC is a light composite building material with building lime as binding agents and hemp (Cannabis sativa) as a renewable raw material from agriculture. Contemporary LHC only uses the woody core part of the hemp, the shive. However, using both hemp shives and fibres may improve the mechanical strength, eliminating the need for a fibre separation process. The aim was to elucidate the feasibility of using the entire fragmented hemp stalk in an LHC, and to determine some important material properties such as compressive strength, splitting tensile strength, water sorption and frost resistance. LHC with varying inclusions of the lime-based binders were tested, as were five mixes using the binding agents hydrated lime, hydraulic lime, and cement. Specimens were cured for 12 weeks at room temperature and 40 days in a carbonation room (4.5 vol% CO2), and tested for mechanical properties, water sorption and frost resistance. Using both shives and fibres in LHC may be advantageous for countries such as Sweden where facilities for separating hemp from shives are not commercially available.
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| 9. |
- De Toro, Alfredo, et al.
(author)
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Cereal harvesting : Strategies and costs under variable weather conditions
- 2012
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In: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 111:4, s. 429-439
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Journal article (peer-reviewed)abstract
- This study simulated 30 years of harvesting operations on an hourly basis with a harvesting model linked to a grain moisture model capable of predicting the moisture content of standing ripe wheat using historical weather data from Stockholm, Sweden, as input, in order to assess the effects of weather on cereal harvesting costs. Several combinations of harvester size and grain moisture ceiling were assessed on three cereal areas in terms of overall costs (machine + labour + timeliness + drying) and their annual variations.The main findings obtained by simulation and valid for regions with similar climate and agricultural conditions to the studied region were that: (a) available combining time was highly dependent on grain moisture ceiling, which showed large annual variation, e.g. a moisture ceiling of 21% (w.b.) was related to a potential harvesting time of 65% and a standard deviation of 24% (n = 30 years); (b) in order to complete harvesting operations in most years, it was necessary to operate at a moisture ceiling of 22-24% (w.b.), however, the average moisture content of the harvested grain was much lower, about 17-18%; (c) overall harvesting costs were estimated at approx €140 ha -1 for those systems performing relatively well, i.e. with a daily harvesting capacity of 4-5% of the cereal area and operating at a moisture ceiling of 22-24% (w.b.); and (d) the main sources of annual cost variation were firstly the timeliness costs and secondly the drying costs. © 2012 IAgrE.
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| 10. |
- Ericson, Stefan K., 1974-, et al.
(author)
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Analysis of two visual odometry systems for use in an agricultural field environment
- 2018
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In: Biosystems Engineering. - London : Elsevier. - 1537-5110 .- 1537-5129. ; 166, s. 116-125
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Journal article (peer-reviewed)abstract
- This paper analyses two visual odometry systems for use in an agricultural field environment. The impact of various design parameters and camera setups are evaluated in a simulation environment. Four real field experiments were conducted using a mobile robot operating in an agricultural field. The robot was controlled to travel in a regular back-and-forth pattern with headland turns. The experimental runs were 1.8–3.1 km long and consisted of 32–63,000 frames. The results indicate that a camera angle of 75° gives the best results with the least error. An increased camera resolution only improves the result slightly. The algorithm must be able to reduce error accumulation by adapting the frame rate to minimise error. The results also illustrate the difficulties of estimating roll and pitch using a downward-facing camera. The best results for full 6-DOF position estimation were obtained on a 1.8-km run using 6680 frames captured from the forward-facing cameras. The translation error (x,y,z) is 3.76% and the rotational error (i.e., roll, pitch, and yaw) is 0.0482 deg m−1. The main contributions of this paper are an analysis of design option impacts on visual odometry results and a comparison of two state-of-the-art visual odometry algorithms, applied to agricultural field data.
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