| 1. |
- Hamid Muhammed, Hamed, et al.
(författare)
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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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Ingår i: Biosystems Engineering. - 1537-5110 .- 1537-5129. ; 86:2, s. 125-134
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 99:1, s. 145-155
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 226, s. 194-208
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Effect of exposed surface area on ammonia emissions from untreated, separated, and digested cattle manure
- 2021
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 202, s. 66-78
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Tidskriftsartikel (refereegranskat)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. |
- Das, Atanu Kumar, et al.
(författare)
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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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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 209, s. 210-215
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Tidskriftsartikel (refereegranskat)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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| 6. |
- Das, Atanu Kumar, et al.
(författare)
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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
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 209, s. 210-215
-
Tidskriftsartikel (refereegranskat)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. |
- De Bruijn, Paulien, et al.
(författare)
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Mechanical properties of lime-hemp concrete containing shives and fibres
- 2009
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 103:4, s. 474-479
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Tidskriftsartikel (refereegranskat)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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| 8. |
- De Toro, Alfredo, et al.
(författare)
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Cereal harvesting : Strategies and costs under variable weather conditions
- 2012
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 111:4, s. 429-439
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Ericson, Stefan K., 1974-, et al.
(författare)
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Analysis of two visual odometry systems for use in an agricultural field environment
- 2018
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Ingår i: Biosystems Engineering. - London : Elsevier. - 1537-5110 .- 1537-5129. ; 166, s. 116-125
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Gebresenbet, Girma, et al.
(författare)
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Cluster Building and Logistics Network Integration of Local Food Supply Chain
- 2011
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 108, s. 293-302
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Tidskriftsartikel (refereegranskat)abstract
- Food supply chain is the current focus in terms of food safety and environment. The objective of this study was to investigate the local food supply chain characteristics and develop a coordinated distribution system to improve logistics efficiency, reduce environmental impact, increase potential market for local food producers and improve traceability of food origin for consumers. The study was based on data from 90 local food producers and 19 existing large scale food distribution centres (LSFDC) from all over Sweden. Location analysis was done using Geographic Information System (GIS), to map locations of producers and LSFDCs; to build cluster (C) of producers; and to determine optimal product collection centres (CC). The route analysis was carried out using Route LogiX software, firstly for collection of food products from farms to CCs based on two Scenarios: (1) Producers transport their products (no coordination); (2) CCs manage coordinated collection of products; and secondly for product distribution from CCs to potential markets. When compared to scenario1, scenario2 had improved number of routes, driving distance and product delivery time by 68%, 50% and 47% respectively. Totally, 14 clusters of producers were formed and 86% of these clusters could be integrated into the LSFDCs. This network integration could have positive improvements towards potential market, logistics efficiency, environmental issue and traceability of food quality
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| 11. |
- Gebresenbet, Girma, et al.
(författare)
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Vibration levels and frequencies on vehicle and animals during transport
- 2011
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 110, s. 10-19
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Tidskriftsartikel (refereegranskat)abstract
- During transport, animals are subjected to various stressors, including vibration, noise and poor handling, and these compromise animal welfare. This study determined vibration levels and resonance frequencies for vehicles and dairy cows. A Volvo FM12 with air suspension, driven at 30, 50, 70 or 90 km h1 on three road types, was used for transportation. To study the effect of standing orientation on vibration, animals were positioned parallel or perpendicular to the direction of travel. Vehicle speed was measured with MAGELLAN 315 type GPS. Two vibration sensors were placed on the chassis and floor and. additional sensors were firmly attached to adjustable straps mounted on animals. For each run, measurements were made over a 20 s period on five animals. The highest vibration level observed on animals was 2.27 0.33 m s2 when driving on gravel roads at 70 km h1. Vibrations in the horizontal and lateral directions were lower on animals positioned perpendicular to the direction of travel than on those facing forward. Both road conditions ( p < 0.0002) and standing orientation ( p < 0.002) have a significant effect on vibration levels. Three main resonance frequencies were identified for the vertical direction, at 1.3, 5.1, 12.6 Hz, and at about 23 Hz. The vibration exposure values (8 h transport period) for the vertical, horizontal and lateral directions were 0.61 0.12, 0.92 0.35, and 1 0.21 m s2, respectively. These exceed the EU daily exposure action of 0.5 m s2, but are lower than the daily exposure limit of 1.15 m s2.
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| 12. |
- Gronskyte, Ruta, et al.
(författare)
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Monitoring pig movement at the slaughterhouse using optical flow and modified angular histograms
- 2016
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 141, s. 19-30
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Tidskriftsartikel (refereegranskat)abstract
- We analyse the movement of pig herds through video recordings at a slaughterhouse by using statistical analysis of optical flow (OF) patterns. Unlike the previous attempts to analyse pig movement, no markers, trackers nor identification of individual pigs are needed. Our method handles the analysis of unconstrained areas where pigs are constantly entering and leaving. The goal is to improve animal welfare by real-time prediction of abnormal behaviour through proper interventions. The aim of this study is to identify any stationary pig, which can be an indicator of an injury or an obstacle. In this study, we use the OF vectors to describe points of movement on all pigs and thereby analyse the herd movement. Subsequently, the OF vectors are used to identify abnormal movements of individual pigs. The OF vectors, obtained from the pigs, point in multiple directions rather than in one movement direction. To accommodate the multiple directions of the OF vectors, we propose to quantify OF using a summation of the vectors into bins according to their angles, which we call modified angular histograms. Sequential feature selection is used to select angle ranges, which identify pigs that are moving abnormally in the herd. The vector lengths from the selected angle ranges are compared to the corresponding median, 25th and 75th percentiles from a training set, which contains only normally moving pigs. We show that the method is capable of locating stationary pigs in the recordings regardless of the number of pigs in the frame.
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| 13. |
- Hamid Muhammed, Hamed
(författare)
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Hyperspectral crop reflectance data for characterising and estimating fungal disease severity in wheat
- 2005
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 91:1, s. 9-20
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Tidskriftsartikel (refereegranskat)abstract
- Many studies have shown the usefulness of hyperspectral crop reflectance data for detecting plant pathological stress. However, there is still a need to identify unique signatures for specific stresses amidst the constantly changing background associated with normal crop growth and development. Comparing spatial and temporal patterns in crop spectra can provide such signatures. This work was concerned with characterising and estimating fungal disease severity in a spring wheat crop. This goal can be accomplished by using a reference data set consisting of hyperspectral crop reflectance data vectors and the corresponding disease severity field assessments. The hyperspectral vectors were first normalised into zero-mean and unit-variance vectors by performing various combinations of spectral- and band-wise normalisations. Then, after applying the same normalisation procedures to the new hyperspectral data, a nearest-neighbour classifier was used to classify the new data against the reference data. Finally, the corresponding stress signatures were computed using a linear transformation model. High correlation was obtained between the classification results and the corresponding field assessments of fungal disease severity, confirming the usefulness and efficiency of this approach. The effects of increased disease severity could be characterised by analysing the resulting disease signatures obtained when applying the different normalisation procedures. The low computational load of this approach makes it suitable for real-time on-vehicle applications.
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| 14. |
- Hung, Chih-Yu, et al.
(författare)
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Manure temperature prediction for slurry storage in Sweden : Model validation including effects of shading, snow cover and mixing
- 2024
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 243, s. 70-81
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Tidskriftsartikel (refereegranskat)abstract
- Measuring and modelling manure temperatures are crucial for estimating greenhouse gas emissions from liquid manure storage. The manure temperature was recorded at various depths in two swine slurry storage tanks situated in Vallentuna (VA) and Örsundsbro (OR) in Sweden. These data were used to assess the effectiveness of a revised mechanistic model for estimating manure temperatures, which incorporates the effects of wall shading, snow cover, and manure input mixing. The average manure temperatures were higher than air temperatures in the summer and fall. This indicated that using air temperature would result in an underestimation of methane emissions when applying the 2019 IPCC Refinement methodology. The revised model estimated manure temperatures for spring, summer, fall, and winter as 4.8, 16.1, 7.8, and 2.6 °C at the VA tank and 11.6, 17.1, 9.5, and 3.6 °C at the OR tank. The root mean square errors between daily simulated and observed temperatures in the summer decreased in both tanks due to incorporating shadow effect into the revised model. Fall estimates did not improve, possibly because of uncertainties from slurry removal and higher precipitation inputs. Sensitivity analysis indicated that solar radiative heat input was reduced with higher tank walls and smaller tank diameters when applying the revised model. Wall shading may influence manure temperatures in tanks with small diameters at high-latitude locations. This study offers insights into understanding the relationship between manure temperatures and its thermal balance influenced by latitude, storage design, snow cover and mixing, and its implications for accurately estimating methane emissions.
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| 15. |
- Keller, Thomas
(författare)
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Feasibility study on the potential of electrical conductivity sensor Veris (R) 3100 for field mapping of topsoil strength
- 2014
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 126, s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- With advances in technology for precision agriculture, numerous attempts have been made towards development of on-the-go sensors for measuring soil compaction. Most of the on-the-go sensors developed so far have been mechanical sensors providing a soil strength parameter that can be related to degree of soil compactness. In this study, a commercial electrical conductivity sensor (Veris (R) 3100) in combination with a previously developed combined horizontal penetrometer (equipped with a dielectric sensor for water content) were tested in a field in order to examine whether the apparent electrical conductivity (ECa) within the 0-0.3 m depth (ECa-shallow) could be helpful in detecting the topsoil strength (here the horizontal penetrometer resistance). Interpolated field maps of horizontal penetrometer resistance (PR), volumetric water content (theta(v)) and ECa showed comparable patterns within some areas (but not over the field). No significant correlation (but a negative trend) was found between ECa and dry bulk density. A significant correlation between ECa and PR/theta(v), (a previously proposed water content-independent PR) was found (R-2 = 0.37, P < 0.0001). However, ECa was strongly affected by soil water content and texture. It was concluded that PR may be indirectly related to ECa through theta(v), which greatly affects both ECa and PR. The results suggested that the EC sensor could potentially be helpful for detecting zones of high soil strength (i.e. high PR/theta(v)). Further studies are suggested to address whether ECa is better related to the state of soil compaction at dry state of soil due to more significant effect of soil-soil electrical conductivity. (C) 2014 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 16. |
- Keller, Thomas
(författare)
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Soil rut depth prediction based on soil strength measurements on typical Estonian soils
- 2017
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 163, s. 78-86
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Tidskriftsartikel (refereegranskat)abstract
- Deep ruts in soil hinder the movement of off-road vehicles and harm drastically the soil environment. The aim of this study was to determine the most suitable cone and remoulding index based methods for rut depth estimation for single and repeated military vehicle passage in typical Estonian soils. Cone index based sinkage models - US Army ERDC, Maclaurin (1990) and Willoughby and Tumage sinkage models applicable for military vehicles were tested, using different critical layers (0-15 cm, 7.5-23 cm or 15-30 cm). The test vehicles were a 7 Mg truck and a 23 Mg armoured personnel carrier. At eight experimental sites covering mechanically very variable soil conditions (from peat to clay soil), rut depth was measured after one and ten vehicle passes, cone penetration tests were conducted in situ, and samples were collected for determination of bulk density, organic carbon content, texture, gravimetric water content, plastic and liquid limits of the topsoil and subsoil. According to average RMSD values for military truck the Willoughby and Turnage model was the most accurate prediction method. For one pass and 10 passes the rating cone index values from the 7.5-23 cm and 15-30 cm soil layer, respectively, produced the lowest RMSD values. (C) 2017 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 17. |
- Kurtser, Polina, 1990-, et al.
(författare)
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Statistical models for fruit detectability: spatial and temporal analyses of sweet peppers
- 2018
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Ingår i: Biosystems Engineering. - : Academic Press. - 1537-5110 .- 1537-5129. ; 171, s. 272-289
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Tidskriftsartikel (refereegranskat)abstract
- Statistical models for fruit detectability were developed to provide insights into preferable variable configurations for better robotic harvesting performance.The methodology includes several steps: definition of controllable and measurable variables, data acquisition protocol design, data processing, definition of performance measures and statistical modelling procedures. Given the controllable and measurable variables, a data acquisition protocol is defined to allow adequate variation in the variables, and determine the dataset size to ensure significant statistical analyses. Performance measures are defined for each combination of controllable and measurable variables identified in the protocol. Descriptive statistics of the measures allow insights into preferable configurations of controllable variables given the measurable variables values. The statistical model is performed by back-elimination Poisson regression with a loglink function process. Spatial and temporal analyses are performed.The methodology was applied to develop statistical models for sweet pepper (Capsicum annuum) detectability and revealed best viewpoints. 1312 images acquired from 10 to 14 viewpoints for 56 scenes were collected in commercial greenhouses, using an eye-in-hand configuration of a 6 DOF manipulator equipped with a RGB sensor and an illumination rig. Three databases from different sweet-pepper varieties were collected along different growing seasons.Target detectability highly depends on the imaging acquisition distance and the sensing system tilt. A minimum of 12 training scenes are necessary to discover the statistically significant spatial variables. Better prediction was achieved at the beginning of the season with slightly better prediction achieved in a temporal split of training and testing sets.
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| 18. |
- Lagnelöv, Oscar, et al.
(författare)
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Cost analysis of autonomous battery electric field tractors in agriculture
- 2021
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Ingår i: Biosystems Engineering. - : Elsevier. - 1537-5110 .- 1537-5129. ; 204, s. 358-376
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Tidskriftsartikel (refereegranskat)abstract
- Interest in the electrification of agricultural vehicles is increasing along with growing interest in autonomous vehicles. Individual technologies have been well-explored, but not their combined use and the effects on agricultural fieldwork. In this study, cost analysis was conducted based on a simulated vehicle system with 50 kW self-driving battery electric drive (BED) tractors. The analysis included battery degradation due to cycling and the cost of inadequate machine capacity, as these factors are suspected to be problems for electric tractors. A dynamic discrete-event vehicle system model, a linear timeliness model and a one-dimensional battery cell ageing model were assumed. Costs obtained were compared with those of contemporary manned diesel-based systems. BED systems had equal or lower annual costs compared to conventional manned diesel-based systems; this was due to lower costs for fuel and maintenance, while providing adequate capacity and lower energy usage. Sensitivity analysis showed that operating costs were of greater significance than investment costs. The generally more expensive investment costs of BED systems were outweighed by the reduced operating costs for several different BED system systems. Battery degradation costs and timeliness were influential, but not sufficient to make the system uncompetitive. The synergistic effect of vehicular autonomy and BED outweighed several of the drawbacks of BED systems, such as frequent recharging, increased transport and reduced consecutive work time.
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| 19. |
- Lagnelöv, Oscar, et al.
(författare)
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Performance comparison of charging systems for autonomous electric field tractors using dynamic simulation
- 2020
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 194, s. 121-137
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Tidskriftsartikel (refereegranskat)abstract
- A model simulating an autonomous battery electric vehicle system for agricultural field use was created, assuming a 200-ha conventional cereal farm in Swedish conditions. The different subsystems were verified against sources in the literature, field experiments and general common practice. The model was used to compare two different charging systems (conductive charging and battery exchange) for battery electric tractors to each other. A comparative simulation was made with conventional diesel systems (fully autonomous or manned for 10 h d(-1)). The simulation results indicated that battery exchange was generally a faster system than conductive charging. The results also showed that both electric systems were able to achieve similar active time during spring field operations as a corresponding system of a simulated manned diesel tractor for battery sizes from 50 kWh and charge powers from 50 kW. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of IAgrE.
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| 20. |
- Larsson, Gunnar, et al.
(författare)
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Environmental impact of catalytic converters and particle filters for agricultural tractors determined by life cycle assessment
- 2011
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 109, s. 15-21
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Tidskriftsartikel (refereegranskat)abstract
- Emissions from agricultural tractors have a detrimental impact on health and the environment. Stricter emission standards have resulted in great reductions in emissions from new vehicles. However, the long life time of tractors means that emissions from older vehicles remain substantial. One way to reduce these emissions is to retrofit catalytic converters, but the manufacture and use of catalytic converters consumes resources and slightly reduces engine efficiency. Life cycle assessment (LCA) can be used to determine their full environmental impact. This study considered three after-treatment options: no retrofit; a diesel oxidation catalyst (DOC)/diesel particulate filter (DPF) system; and a selective catalytic reduction (SCR) catalytic converter. Two vehicle usage patterns were considered, one following the legal test cycle (used for all off-road vehicles) and one corresponding to average agricultural tractor usage. With most of the assessment methods used in LCA, the impact change was small and totally dominated by changes in tractor emissions. All assessment methods gave the SCR catalytic converter a better value than the DOC/DPF system. The DOC/DPF system decreased the impact on human health, while the SCR catalytic converter decreased the acidification and eutrophication impact. Both catalytic converter increased abiotic resource consumption substantially. The legal test cycle produced similar results to the agricultural tractor usage cycle
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| 21. |
- Larsson, Gunnar, et al.
(författare)
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Evaluation of factors influencing emissions from tractors and construction equipment during realistic work operations using diesel fuel and bio-fuels as substitute
- 2010
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 107, s. 123-130
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Tidskriftsartikel (refereegranskat)abstract
- Swedish Environmental Class One (MK1) diesel fuel and three diesel substitutes were compared during steady state conditions, during transients and during work operations commonly performed by tractors and construction equipment. This was carried out in order to determine how fuel, typical engine load/speed and transient effects influence emissions and engine efficiency during common work operations.The results showed that the differences between the fuels were small, except for particulates. Differences in typical engine load/speed and transients effects could; however, cause emissions to vary between 0.5 and 3 times those expected from the current (steady state) ISO 8178C1 cycle, whilst the fuel consumption was only moderately affected. Transient effects appeared to be able to double the emissions. (C) 2010 Published by Elsevier Ltd on behalf of IAgrE.
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| 22. |
- Le, Kim-Cuong, et al.
(författare)
-
Evaluation of parameters to characterise germination-competent mature somatic embryos of Norway spruce (Picea abies)
- 2021
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 203, s. 55-59
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Tidskriftsartikel (refereegranskat)abstract
- Somatic embryogenesis (SE) is an in vitro clonal propagation method increasingly in use for large scale clonal propagation of conifer plants. However, asynchronous development of immature somatic embryos into mature embryos lowers the yield of plants and limits the benefits for industrial applications. Through the development of an automated harvesting system (SE Fluidics system) for singulation, imaging and selection of mature embryos at the correct developmental stages, yields can be improved. Image analysis software developed for use with the SE Fluidics system has been utilised to characterize and sort mature embryos according to their morphological measurements related to developmental capacity. Here a set of imaging data from the SE Fluidics system has been analysed with the goal of further refining the selection criteria for germination-competent mature embryos.(c) 2021 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 23. |
- Martin Ngwabie, Ngwa, et al.
(författare)
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Multi-location measurements of greenhouse gases and emission rates of methane and ammonia from a naturally-ventilated barn for dairy cows
- 2009
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 103, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- The building had 164-195 Holstein dairy cows. The milk production was 31-33 kg cow(-1)d(-1). Manure gutters beneath the partially slatted floor in the building were scraped twice a day. Measurements took place during the winter when the cows were permanently indoors and during 1 week in the spring when the cows were indoors at night and outside grazing during the daytime. The indoor concentrations were measured at nine evenly distributed locations, while outdoor concentrations were measured at two locations. The mean ventilation rate in winter was 250-26S m(3) LU(-1) h(-1) and in spring, it was 401 m(3) LU(-1) h(-1). The emissions of NH3 and CH(4) were in the range of 0.89-1.13 and 9-13 g LU-1 h-1, respectively. A strong positive correlation was found between enhanced CO(2) and CH(4) concentrations. (C) 2009 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 24. |
- Marx, Christian, 1975, et al.
(författare)
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Investigations on laser marking of plants and fruits
- 2013
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5129 .- 1537-5110. ; 116:4, s. 436-446
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Tidskriftsartikel (refereegranskat)abstract
- High traceability has become more and more important for worldwide logistics of horticultural products as the flow of goods rises steadily. Barcode stickers are widely used on product packaging or on the product itself. Direct product marking could be an option, to improve marking safety and to increase protection against forgery. Therefore, this paper investigates the benefits of direct laser marking and identifies the factors influencing the achievement of useable markings. The studies were conducted by testing various laser wavelengths (193-10,600nm) to mark a simple 9mm2 sized 2-D barcode on the surface of apple fruits and rhododendron cuttings. Depending on the laser wavelength, the process steps of laser marking, the risk of fungal infection and the marking pattern alteration due to product storage were investigated. The marking process (laser energy, laser wavelength, pattern size, pattern design, etc.) considerably influences the representation accuracy of the patterns used, which is important for later image processing. By using suitable laser marking energies per pattern, it is possible to minimise the damaging of product surfaces, and correspondingly the risk of fungal infection. This leads to an applicable codification of individual horticultural products. © 2013 IAgrE.
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| 25. |
- Midtiby, Henrik Skov, et al.
(författare)
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Upper limit for context-based crop classification in robotic weeding applications
- 2016
-
Ingår i: Biosystems Engineering. - London : Academic Press. - 1537-5110 .- 1537-5129. ; 146, s. 183-192
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the precise position of crop plants is a prerequisite for effective mechanical weed control in robotic weeding application such as in crops like sugar beets which are sensitive to mechanical stress. Visual detection and recognition of crop plants based on their shapes has been described many times in the literature. In this paper the potential of using knowledge about the crop seed pattern is investigated based on simulated output from a perception system. The reliability of position–based crop plant detection is shown to depend on the weed density (ρ, measured in weed plants per square metre) and the crop plant pattern position uncertainty (σx and σy, measured in metres along and perpendicular to the crop row, respectively). The recognition reliability can be described with the positive predictive value (PPV), which is limited by the seeding pattern uncertainty and the weed density according to the inequality: PPV ≤ (1 + 2πρσxσy)−1. This result matches computer simulations of two novel methods for position–based crop recognition as well as earlier reported field–based trials. © 2016 IAgrE
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| 26. |
- Nilsson, Daniel, et al.
(författare)
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Dynamic modelling of cut-and-store systems for year-round deliveries of short rotation coppice willow
- 2017
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 159, s. 70-88
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Tidskriftsartikel (refereegranskat)abstract
- Short rotation coppice willow (SRCW) is a high-yielding energy crop that can be used to produce solid, liquid or gaseous biofuels. The crop is harvested during the winter, when the leaves have dropped. For economic reasons, however, most fuel processing plants require continuous year-round delivery of raw material. Thus, SRCW should be harvested as stems or in larger pieces in order to be storable, and not chipped directly at harvest for immediate use in large-scale heating plants, which is common practice at present. The aim of the project within which this study was conducted is to find cost-effective whole-stem harvesting and handling systems for year-round deliveries of natural-dried SRCW. A discrete event simulation model for such systems was developed in this study, taking weather, soil trafficability, geographical conditions, natural drying of the material and storage losses into account. The model was applied to a fictitious processing plant in Uppsala, Sweden. Machine performance and costs for a system with one stem harvester and up to three infield shuttles, together with one chipper truck for chipping and transport, were investigated. The simulations showed that field trafficability had a crucial impact on total quantity harvested. The total cost was 40 t(-1) dry matter. Yield of SRCW and harvest productivity were important factors regarding costs. The model can be used to design cost-effective harvesting and handling systems for year-round deliveries of SRCW. (C) 2017 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 27. |
- Nimmermark, Sven
(författare)
-
Airborne pollutant emissions from naturally ventilated buildings: Proposed research directions
- 2013
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 116, s. 214-220
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Tidskriftsartikel (refereegranskat)abstract
- 4. Establish a dedicated facility that could be used to obtain precise reference measurements of ventilation rates in naturally ventilated building. To enable this, a parallel development of new technologies (instrumentation and methodology) is required. (C) 2013 Published by Elsevier Ltd on behalf of IAgrE.
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| 28. |
- Nimmermark, Sven
(författare)
-
Influence of odour concentration and individual odour thresholds on the hedonic tone of odour from animal production
- 2011
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 108, s. 211-219
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Tidskriftsartikel (refereegranskat)abstract
- Odours constitute a problem when they affect the health of those exposed or when their character and intensity cause annoyance. Odour concentration and the hedonic tone of odours are of interest when setback models are used to predict annoyance in the neighbourhood of odour emitting operations. An experiment was made with the objective of studying the relationship between the odour concentration and the hedonic tone of odours from pig, poultry and dairy operations. A further objective was to identify individual factors of importance for rating of the hedonic tone. A panel of 16 persons was engaged to rate the hedonic tone and for each panel member the individual odour threshold for n-butanol was estimated. Odour samples from poultry and livestock buildings were analysed for odour concentration following European guidelines. The panel members rated the hedonic tone of various odour concentrations. Odour concentration explained much of the hedonic tone of odour from pigs, pig manure and laying hens. For Odour from dairy cows, the odour concentration explained comparatively less. On a hedonic scale, where 0 is neutral and -4 is extremely unpleasant, an odour concentration of 14-16 European odour units (ou(E)) m(-3) from pig and poultry houses was rated to -1. On the same scale, an odour concentration of 37 ou(E) m(-3) from a cow shed was rated to -1. Individual odour thresholds were found to be important for rating of the hedonic tone. The rating of the hedonic tone showed similarity to odour intensities reported in other studies. (C) 2010 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 29. |
- Persson, Maria, et al.
(författare)
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Classification of crops and weeds extracted by active shape models
- 2008
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Ingår i: Biosystems Engineering. - New York : Elsevier. - 1537-5110 .- 1537-5129. ; 100:4, s. 484-497
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Tidskriftsartikel (refereegranskat)abstract
- Active shape models (ASMs) for the extraction and classification of crops using real field images were investigated. Three sets of images of crop rows with sugar beet plants around the first true leaf stage were used. The data sets contained 276, 322 and 534 samples, equally distributed over crops and weeds. The weed populations varied between the data sets resulting in from 19% to 53% of occluded crops. Three ASMs were constructed using different training images and different description levels. The models managed to correctly extract up to 83% of the crop pixels and remove up to 83% of the occluding weed pixels. Classification features were calculated from the shapes of extracted crops and weeds and presented to a k-NN classifier. The classification results for the ASM-extracted plants were compared to classification results for manually extracted plants. It was judged that 81–87% of all plants extracted by ASM were classified correctly. This corresponded with 85–92% for manually extracted plants.
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| 30. |
- Prade, Thomas, et al.
(författare)
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Including a one-year grass ley increases soil organic carbon and decreases greenhouse gas emissions from cereal-dominated rotations – A Swedish farm case study
- 2017
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 164, s. 200-212
-
Tidskriftsartikel (refereegranskat)abstract
- Increased soil organic carbon (SOC) content has been shown to increase soil fertility and carbon sequestration, but SOC changes are frequently neglected in life cycle assessment (LCA) studies of crop production. This study used a novel LCA application using simulated SOC changes to examine the greenhouse gas (GHG) impact of a combined food and energy crop production from a crop rotation perspective. On a case pig farm, introduction of one year of grass ley into a cereal-dominated crop rotation was simulated. The grass and pig manure were used for biogas production and the digestion residues were used as fertiliser on the farm. This crop rotation shift increased the SOC stocks by an estimated 27 and 49% after 50 years and at steady state, respectively. The estimated corresponding net wheat yield increase due to higher SOC was 8–16% and 16–32%, respectively, indicating that initial loss of low-yield oat production can be partly counterbalanced. Net SOC increase (corresponding to 2 t CO2-eq ha−1 a−1) was the single most important variable affecting the GHG balance. When biogas replaced fossil fuels, GHG emissions of the combined energy-food crop rotation were approx. 3 t CO2-eq ha−1 a−1 lower than for the current food crop rotation. Sensitivity analyses led to variation of only 2–9% in the GHG balance. This study indicates that integrated food and energy crop production can improve SOC content and decrease GHG emissions from cropping systems. It also demonstrates the importance of including SOC changes in crop production-related LCA studies.
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| 31. |
- Rodhe, Lena, et al.
(författare)
-
Ammonia emissions from broiler manure : Influence of storage and spreading method
- 2002
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 82:4, s. 455-462
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge is poor concerning losses of ammonia from broiler manure during storage and after spreading. Broiler manure was stored from October to May in two separate heaps, one uncovered and one covered with a 30 cm layer of straw. Ammonia emissions were measured with a micrometeorological mass balance method in five separate periods during storage. Ambient air temperature and temperatures in the heaps were recorded continuously. After storage, broiler manure from the uncovered heap and commercial fertilizer pellets including broiler manure were spread to arable land at a rate of 110 kg [total-N] ha-1. Ammonia emissions were measured with an equilibrium concentration method from plots fertilized with broiler manure and pellets, respectively, with and without harrowing 4 h after spreading. Temperature measurements taken in the heaps during storage indicated high biological activity. The highest temperatures were recorded in the straw-covered heap. Cumulative ammonia losses were 7% of total nitrogen from the uncovered heap and 10% from the heap with cover. Totally, 13.5% of the nitrogen in the broiler manure was lost as ammonia after spreading without incorporation of the manure and 7.5% from plots with incorporation. After incorporation no ammonia emission occurred. No emissions occurred from plots fertilized with pellets. © 2002 Silsoe Research Institute. Published by Elsevier Science Ltd. All rights reserved.
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| 32. |
- Rodhe, Lena, et al.
(författare)
-
Application of slurry to ley by band spreading and injection methods
- 2002
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 83:1, s. 107-118
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, 90% of the total amount of ammonia released to air originates from agriculture, e.g. manure handling. Incorporation of slurry into soil can reduce ammonia emissions after spreading. The objective of this study was to compare cattle slurry application to ley using (1) band spreading, (2) pressurized injection, and shallow injection with two different types of disc tines (3) and (4). Two years of field experiments were conducted to study slurry position after spreading, ammonia volatilization, grass yield, and silage quality. An economic analysis was also performed. Injection (2) and (3) were unable to satisfactorily incorporate the slurry, neither on a loam under dry soil conditions, nor on a clay soil. Year 1, high ammonia emissions were measured following application by all methods. Injector (3) with V-shaped disc tines gave a significantly (probability P<0.05) higher ammonia release compared to the other methods. Injector (3) also gave a significantly better silage quality than band spreading. Year 2, injector (4) with tines consisting of two-angled disc coulters resulted in the lowest ammonia losses. Certain differences in yield were observed in year 2. Computer simulations showed, that broadcast and band spreading were economically more profitable than shallow injection. © 2002 Silsoe Research Institute. Published by Elsevier Science Ltd. All rights reserved.
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| 33. |
- Rodhe, Lena, et al.
(författare)
-
Greenhouse gas emissions from pig slurry during storage and after field application in northern European conditions
- 2012
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 113:4, s. 379-394
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Tidskriftsartikel (refereegranskat)abstract
- Different mitigation techniques for greenhouse gas (GHG) emissions from pig slurry in storage and after field application were evaluated and specific emissions factors derived. Fluxes of methane (CH4) and nitrous oxide (N2O) were measured for one year in a pilot-scale storage plant comparing uncovered pig slurry (NC) with slurry covered by straw (SC) or plastic sheet cover (PC). In spring and autumn, stored slurry was band spread (BS) in the field without or with immediate incorporation by harrowing (BS + HA). Closed chamber techniques were used for gas sampling. Complementary soil core experiments in the laboratory examined the influence of soil moisture and temperature on emissions from slurry application. Annual CH4 emissions (g CH4-C kg-1 VS) from storage were 5.3 for NC, 5.8 for SC and 2.8 for PC, corresponding to CH4 conversion factors (MCFs) of 2.6, 2.8 and 1.4%, respectively. N2O emissions from storage were low except from SC, where they comprised 31.7 g N2O-N m-2 year-1, corresponding to an N2O emissions factor (EFN2O) of 0.66% of total N (Tot-N) in slurry. N2O emissions after field application varied depending on soil conditions, with soil moisture content having a significant influence according to soil core experiments. Overall, cumulative N2O-N emissions in spring were 1.35% of Tot-N in slurry for BS and 0.46% for BS + HA. Corresponding N2O-N emissions in autumn were 0.77 and 0.97%. The MCFs observed in storage were considerably lower than the default IPCC value of 10%, while EFN2O was in the suggested IPCC range for storage and field.
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| 34. |
- Rodhe, Lena, et al.
(författare)
-
Performance of slurry injectors compared with band spreading on three Swedish soils with ley
- 2005
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 92:1, s. 107-118
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of the present study was to evaluate different injection methods for slurry to ley on three different soils. A further objective was to study the effect of soil moisture on the working depth of an injector and on the slurry infiltration rate. In full-scale experiments, the placement of slurry, ammonia emissions and yield were measured after injection with three techniques: pressurised injection, shallow injection with V-shaped discs, and shallow injection with two angled discs. In an adjacent experiment the effect of soil moisture was studied. The performance varied between the injectors and only the injector with angled discs was able to place the slurry in ley below the soil surface on all soils studied. The ammonia release was on average halved after injection with angled discs compared with band spreading, giving a mean ammonia loss of 39% of the total ammoniacal nitrogen (TAN) applied. Despite the reduction in ammonia losses with the angled disc injector, this did not result in higher dry matter yield or higher nitrogen efficiency of the second cut compared with band spreading. The working depth of a slurry injector increased significantly with increasing soil water content. © 2005 Silsoe Research Institute. All rights reserved.
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| 35. |
- Rodhe, Lena, et al.
(författare)
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The influence of shallow injector design on ammonia emissions and draught requirement under different soil conditions
- 2004
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 89:2, s. 237-251
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Tidskriftsartikel (refereegranskat)abstract
- Incorporation of manure into soil can effectively reduce ammonia emissions after spreading. This study was aimed at finding an appropriate tine design, which shallowly injects slurry in closed slots on grassland, with relatively low draught forces and minimal emissions of ammonia. Hollow 'tubulator' tines were developed in six different designs and compared with a double disc tine. Horizontal and vertical forces were measured in an indoor sand bin and in field experiments. In some field tests slurry placement and ammonia emissions were also measured. With the sharp tip of the smallest tubulator (application rate of 25 t ha -1; depth of 5 cm) the draught forces in the field were from 520 to 1080 N, depending on soil. Draught forces for the double disc tine were similar or slightly lower. However, under all soil conditions, the tubulator required significantly lower vertical forces to penetrate the soil than the double disc tine. For an application rate of 35 t ha -1, draught and vertical forces for the medium-sized tubulators were about half those for the double disc tine at 8 cm depth. Ammonia losses after injection with the tubulator were 1·6% and for the double disc tine 27% of applied ammonia nitrogen. Thus, appropriate tine design can minimise ammonia losses while maintaining similar energy requirements to a conventional injector. © 2004 Silsoe Research Institute. All rights reserved.
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| 36. |
- Roepstorff, Lars
(författare)
-
Comparison of equipment used to measure shear properties in equine arena surfaces
- 2015
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 137, s. 43-54
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Tidskriftsartikel (refereegranskat)abstract
- The design of a novel apparatus, the Glen Withy torque tester (GWTT), for measuring horizontal shear properties in equine sport surfaces is described. Previous research has considered the effect of vertical loading on equine performance and injury but only limited discussion has concerned the grip or horizontal motion of the hoof. The horizontal support of the hoof by the surface must be sufficient to avoid excess slip without overloading the limb. The GWTT measures the torque necessary to twist an artificial hoof that is being pushed into the surface under a consistently applied vertical load. Its output was validated using a steel surface, then was used to test two sand and fibre surfaces (waxed and non-waxed) through rotations of 40-140 degrees, and vertical loads of 157-1138 N. An Orono biomechanical surface tester (OBST) measured longitudinal shear and vertical force, whilst a traction tester measured rotational shear after being dropped onto the surfaces. A weak, but significant, linear relationship was found between rotational shear measured using the GWTT and longitudinal shear quantified using the OBST. However, only the GWTT was able to detect significant differences in shear resistance between the surfaces. Future work should continue to investigate the strain rate and non-linear load response of surfaces used in equestrian sports. Measurements should be closely tied to horse biomechanics and should include information on the maintenance condition and surface composition. Both the GWTT and the OBST are necessary to adequately characterise all the important functional properties of equine sport surfaces. (C) 2015 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 37. |
- Roepstorff, Lars
(författare)
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The effects of varying cushion depth on dynamic loading in shallow sand thoroughbred horse dirt racetracks
- 2013
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 114, s. 178-186
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Tidskriftsartikel (refereegranskat)abstract
- Surface consistency is an important factor for the safety of thoroughbred racing surfaces. Factors that influence the consistency in dirt tracks include homogeneity of surface material composition, moisture content, and cushion depth. The influence of cushion depth on the dynamic load and accelerations experienced by the horse at a range of moisture levels typical to operating conditions (14%, 16%, and 18% gravimetric for the material tested in this work), and surface maintenance conditions (sealed and harrowed), is addressed. A biomechanical surface tester, designed to simulate the forelimb impact of a galloping thoroughbred horse, was repeatedly dropped on five different surface conditions, each at two cushion depths (100 mm and 150 mm). The difference of 50 mm, a depth range often found within a single track had a statistically significant effect on the peak load and the secondary phase loading rate experienced by a horse, particularly under the outlying moisture content conditions (relatively dry or moisture saturated). The tested material behaved more similarly at the two cushion depths under moisture conditions at which maximum dry density occurred (16%). Peak loads and loading rates were significantly different between the two depths for harrowed, 14% moisture conditions, and sealed, 18% moisture conditions. These cushion depths and surface material moisture levels are within normal operating conditions for thoroughbred race meetings on shallow sand tracks and therefore may influence the development of musculoskeletal disease and the safety of horses and jockeys. (C) 2012 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 38. |
- Strandberg-de Brujin, Paulien, et al.
(författare)
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Moisture transport properties of lime-hemp concrete determined over the complete moisture range
- 2014
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 122, s. 31-41
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Tidskriftsartikel (refereegranskat)abstract
- To determine the durability of a lime-hemp concrete (LHC) wall and its resistance to driving rain, moisture conditions inside the wall have to be modelled. As model input, moisture transport properties were determined. Two LHC mixes were studied. Cup tests provided moisture diffusivity results at relative humidity (RH) values up to 95%. Capillary water uptake tests provided results for the interval 95-100% RH by means of curve fitting and the simulation tool JAM-KAP. A mix containing more lime showed higher moisture diffusivity at relative humidity >95%.
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| 39. |
- Ternman, Emma
(författare)
-
Geometrical method for interpolating S-peaks from cow ECG using a microcontroller
- 2015
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 129, s. 324-328
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a new and computationally efficient adaptive geometrical method for improving the resolution of electrocardiogram (ECG) S-peak detection. The target device is an ECG implant for dairy cows which provides limited calculation power. The method utilises only arithmetic operations and is adaptive to individual ECG curves and electrode installation effects. The method tracks the average heights of the sample points preceding and following the S-wave peak. Comparing these heights to the long-time average values provides an estimate of the offset of the peak sample from the actual peak moment. On average, the prediction of spline interpolation on the original 512 Hz turning point is 0.043 ms more accurate than our geometrical algorithm. Both methods result in less than a 0.7 ms difference from the original data. However, the proposed method is significantly more computationally efficient than cubic spline interpolation. (C) 2014 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 40. |
- Trabelsi, S., et al.
(författare)
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Microwave dielectric method for the rapid, non-destructive determination of bulk density and moisture content of peanut hull pellets
- 2013
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 115:3, s. 332-338
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Tidskriftsartikel (refereegranskat)abstract
- A rapid dielectric-based method was used to non-destructively determine the moisture content and bulk density of peanut-hull pellets from free-space measurement of their dielectric properties at microwave frequencies. For moisture content determination, a permittivity-based function was used that permits moisture prediction independent of bulk density from measurement of the dielectric properties at microwave frequencies. For bulk density determination, an analytical expression was obtained from a representation of the dielectric properties in the complex plane. Results of moisture and density prediction from measurement of the dielectric properties are shown at 5, 10, and 15GHz at 22°C. •Dielectric properties of peanut hull pellets were measured in free space between 5GHz and 15GHz at 22°C. © 2013.
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| 41. |
- van Herck, Liesbet, et al.
(författare)
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Crop design for improved robotic harvesting : a case study of sweet pepper harvesting
- 2020
-
Ingår i: Biosystems Engineering. - : Elsevier. - 1537-5110 .- 1537-5129. ; 192, s. 294-308
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Tidskriftsartikel (refereegranskat)abstract
- Current harvesting robots have limited performance, due to the unstructured and dynamic nature of both the target crops and their environment. Efforts to date focus on improving sensing and robotic systems. This paper presents a parallel approach, to "design" the crop and its environment to best fit the robot, similar to robotic integration in industrial robot deployments.A systematic methodology to select and modify the crop "design" (crop and environment) to improve robotic harvesting is presented. We define crop-dependent robotic features for successful harvesting (e.g., visibility, reachability), from which associated crop features are identified (e.g., crop density, internode length). Methods to influence the crop features are derived (e.g., cultivation practices, climate control) along with a methodological approach to evaluate the proposed designs. A case study of crop "design" for robotic sweet pepper harvesting is presented, with statistical analyses of influential parameters. Since comparison of the multitude of existing crops and possible modifications is impossible due to complexity and time limitations, a sequential field experimental setup is planned. Experiments over three years, 10 cultivars, two climate control conditions, two cultivation techniques and two artificial illumination types were performed. Results showed how modifying the crop effects the crops characteristics influencing robotic harvesting by increased visibility and reachability. The systematic crop "design" approach also led to robot design recommendations. The presented "engineering" the crop "design" framework highlights the importance of close synergy between crop and robot design achieved by strong collaboration between robotic and agronomy experts resulting in improved robotic harvesting performance.
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| 42. |
- von Wachenfelt, Hans, et al.
(författare)
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Design criteria for structural design of silage silo walls
- 2014
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 126, s. 92-103
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Tidskriftsartikel (refereegranskat)abstract
- Existing Swedish design guidelines (JBR) cover silo wall heights up to about 3 m. These guidelines presumably overestimate the forces and pressures exerted by silage juice when silo walls are more than 3 m high, which could result in over-sizing, material waste and increased capital costs. This study determined silage physical properties in terms of horizontal wall pressure and evaluated silage juice levels in silos with a wall height of 3 m or more.Wall pressure was measured by transducers mounted on a steel ladder rack placed vertically along the internal silo wall. The ladder rack also permitted measurement of silage juice levels in slotted steel pipes. The pressure on the transducers was recorded by a data acquisition system displaying static and total loads (pressures imposed by silage material without and with the compaction machine, respectively).The static pressure at the bottom of the silo wall (4 m) was 16 kPa during filling and compaction, and 22 kPa 1-4 months after filling. The silage juice did not interact with compaction. The wall pressure increased by 30% after filling, but the increase was only significant at 1 m from the silo bottom. The dynamic load was 17 kPa when the compaction machine passed 0.1 m from the silo wall.New guidelines are proposed based on the results and on the Eurocode for ultimate limit states (ULS) for two stages; filling and the utility period. The design bending moment for ULS was 21% lower than specified in JBR. (C) 2014 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 43. |
- von Wachenfelt, Hans, et al.
(författare)
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Force analysis of unprovoked pig gait on clean and fouled concrete surfaces
- 2009
-
Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 104, s. 250-257
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Tidskriftsartikel (refereegranskat)abstract
- Pigs frequently slip and fall on floors, and in some cases they incur injuries. Several studies have shown inadequate floor properties to be the primary cause of most claw disorders in pigs, but to date no clear relationship has been found between claw disorders and floor properties such as friction and surface abrasiveness. To determine this relationship, the factors controlling gait must be characterised. This study characterised unprovoked pig gait on clean and fouled concrete floor conditions by the use of kinetics. A force plate was used to record kinetic gait parameters such as stance time, vertical and horizontal forces, and time of peak vertical force. In a previous study it was shown that pig gait adaption to fouled floor conditions resulted in reduced walking speed and prolonged stance phase. In fouled floor conditions gait adaptation in the present study showed a greater reduction in horizontal forces than in vertical forces, which reduced the peak utilised coefficient of friction (UCOF) and delayed the application of full vertical forces by the fore limbs
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| 44. |
- von Wachenfelt, Hans, et al.
(författare)
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Gait and force analysis of provoked pig gait on clean and fouled concrete surfaces
- 2009
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 104, s. 534-544
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Tidskriftsartikel (refereegranskat)abstract
- Gait and force analysis have proven to be useful methods in linking claw injuries to surface material conditions. To determine the relationship between claw disorders and floor properties such as friction and surface abrasiveness, the factors controlling gait must be characterised. The effects of fouled concrete floor conditions on the gait of 10 pigs walking in a curve, using kinematics and kinetics to record gait parameters and slip frequency are described and compared with clean conditions. Pigs adapted to fouled floor conditions by reducing their walking speed and stride length, using a higher number of 3-foot support phases and by lowering diagonality. This adaption produced lower vertical forces, a twofold reduction in propulsion and outward stabilisation force and a threefold increase in braking force, without reducing the peak utilised coefficient of friction (UCOF). The UCOF values for both limbs of the curve walking pigs exceeded the recorded dynamic coefficient of friction and the corresponding UCOF values for pigs walking a straight line in fouled floor condition. As UCOF increased and available friction from the fouled floor surface decreased, this resulted in higher forward and backward slip frequencies in both limbs for pigs walking in a curve. Pigs provoked to walk in a curve can adapt to fouled floor condition, but if the floor is heavily fouled this adaption is not sufficient to ensure safe walking
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| 45. |
- von Wachenfelt, Hans, et al.
(författare)
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Gait and force analysis of provoked pig gait on clean and fouled rubber mat surfaces
- 2010
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 106, s. 86-96
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Tidskriftsartikel (refereegranskat)abstract
- Materials that increase floor friction forces in absorption of foot pressure could reduce the risk of slipping, i.e. promote walking safety. The effects of fouled rubber mat floor condition on the gait of 10 pigs walking in a curve, using kinematics and kinetics to record gait parameters and slip frequency, are described and compared with clean conditions. Pigs adapted to fouled floor conditions through reduced walking speed (10%), prolonged swing and stance time, and a higher number of 3-limb support phases, but kept stride length and diagonality constant. This adaption produced a threefold reduction in lateral horizontal forces and kept braking and propulsion forces constant, resulting in a constant peak utilised coefficient of friction (UCOF) level in fore limbs but a 31% reduction in UCOF in hind limbs. The better traction for pigs walking on rubber matting compared with concrete is due to a more effective transmission of forces from the limb to the elastomer, dissipating the forces into energy within the material, and thus impeding the effect of centripetal force, with less displacement of body centre of gravity and less forward and backward slip. Pig forward slip frequency on fouled rubber matting was 65 and 51% lower for fore and hind limbs respectively compared with pigs walking a curve on fouled concrete. The soft flooring material improved gait adaption and could thus improve walking safety
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| 46. |
- von Wachenfelt, Hans, et al.
(författare)
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Measurement of kick loads from horses on stable fittings and building elements
- 2013
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 116, s. 487-496
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Tidskriftsartikel (refereegranskat)abstract
- Fittings and fixtures in horse stables may cause injuries to horses when trapped and there is a high risk of an accident to animal and handler when releasing a horse. The risk of injuries to horses and handlers must be minimised by correct structural design and appropriate choice of building material. The physical load of unprovoked and provoked horse kicks were measured in order to obtain data for the design of safe horse fittings and fixtures. To record the forces exerted by horse kicks a measuring wall and a computerised measuring system were constructed and used in single horse boxes. For reference, the characteristics of the measuring system were determined by a drop hammer test. Through regression analysis a linear relation was found between the field recorded impact values from horse kicks obtained by the measuring system and drop hammer impact values. The drop hammer method can thus be used to test fittings. Impacts recorded in the field tests were rapid, often shorter than 0.03 s and 90% had a maximum value below 1924 N. The greatest impact force and impulse caused by a horse kick were 8722 N and 131 Ns respectively, with no statistical difference between provoked and unprovoked kicks. Considering the data obtained and allowing a certain safety margin, the impact resistance of horse fixtures and fittings in single horse boxes, to be used for horses of up to 700 kg mass, should be at least equivalent to 150 Ns exerted by a horse shoe at 45°.
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| 47. |
- von Wachenfelt, Hans
(författare)
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Performance of geotextile-gravel bed all-weather surfaces for cattle
- 2011
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 108, s. 46-56
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Tidskriftsartikel (refereegranskat)abstract
- The pad surface layer reduced runoff flow rate and stabilised drain flow throughout the experiments, confirming pad stability. Manure removal reduced total N, total P, chemical oxygen demand (COD) and total solid (TS) concentrations in drainage effluent. One pad construction proved better at oxidising NO(2)-N and another at trapping TS. One pad construction met the sealing liner norm to the underlying soil. The drainage effluent produced was acceptable for wetland treatment. The results show that geotextile and gravel pad constructions not only have a supporting and draining function, but also a filtering, aerating and sealing effect. (C) 2010 IAgrE. Published by Elsevier Ltd. All rights reserved.
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| 48. |
- Chalermchat, Yongyut, et al.
(författare)
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Electropermeabilization of apple tissue: Effect of cell size, cell size distribution and cell orientation
- 2010
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110. ; 105:3, s. 357-366
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Tidskriftsartikel (refereegranskat)abstract
- The influence of the anisotropy of apple tissue and the orientation of applied electric field on electropermeabilization was investigated. Different tissue regions were sampled to perform a series of experiments. The tissue was viewed under the microscope to study cell size, shape and orientation. In a parallel experiment, cylindrical samples of tissue were subjected to pulsed electric fields and the change in electrical conductivity was measured by the voltage-current method. The measured electrical conductivity during pulsing was then converted into a permeability index which defined the relative change in electrical conductivity compared to the electrical conductivity of frozen/thawed tissue that served as a reference of completely damaged tissue. Electrical impedance was also measured to monitor the tissue changes as affected by pulsed electric fields. The results showed that elongated cells taken from the inner region of the apple parenchyma, responded to the electric fields in different ways. Fields of lower intensity were required to permeabilize these cells when the fields were applied parallel to the longest axis of the cells. Other field orientations required greater applied electric fields to permeabilize the cells. No field orientation dependence was observed for round cells that belonged to the outer region of the apple parenchyma. A condition in which a high degree of permeabilization during pulsing and very small change after pulsing were observed could be obtained at an applied field intensity of 900 V cm(-1). Thus reversible electroporation took place. (C) 2009 IAgrE. Published by Elsevier Ltd. All rights reserved.
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