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  Subjects -> AGRICULTURE (Total: 726 journals)
    - AGRICULTURAL ECONOMICS (72 journals)
    - AGRICULTURE (496 journals)
    - CROP PRODUCTION AND SOIL (92 journals)
    - DAIRYING AND DAIRY PRODUCTS (26 journals)
    - POULTRY AND LIVESTOCK (40 journals)

AGRICULTURE (496 journals)                  1 2 3 4 5 | Last

Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
Acta agriculturae Slovenica     Open Access   (Followers: 5)
Acta Agrobotanica     Open Access   (Followers: 4)
Acta Agronomica Hungarica     Full-text available via subscription   (Followers: 1)
Acta Agronomica Sinica     Full-text available via subscription   (Followers: 6)
Acta Scientiarum. Animal Sciences     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access  
Acta Technologica Agriculturae     Open Access   (Followers: 2)
Advances in Agriculture     Open Access   (Followers: 2)
Advances in Agriculture & Botanics     Open Access   (Followers: 10)
Advances in Agronomy     Full-text available via subscription   (Followers: 12)
Advances in Life Science and Technology     Open Access   (Followers: 6)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 20)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Journal of Agricultural Research     Open Access   (Followers: 4)
African Journal of Food Science     Open Access   (Followers: 6)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 12)
African Journal of Horticultural Science     Open Access   (Followers: 2)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 4)
African Journal of Sustainable Development     Full-text available via subscription   (Followers: 7)
Agribusiness : an International Journal     Hybrid Journal   (Followers: 4)
Agricultura Tecnica     Open Access   (Followers: 6)
Agricultura Tropica et Subtropica     Open Access   (Followers: 2)
Agricultural Advances     Open Access   (Followers: 4)
Agricultural and Food Science     Open Access   (Followers: 20)
Agricultural Economics     Hybrid Journal   (Followers: 49)
Agricultural History     Full-text available via subscription   (Followers: 87)
Agricultural History Review     Full-text available via subscription   (Followers: 3)
Agricultural Research     Hybrid Journal   (Followers: 6)
Agricultural Science     Full-text available via subscription   (Followers: 6)
Agricultural Science     Open Access  
Agricultural Sciences     Open Access   (Followers: 8)
Agricultural Sciences in China     Full-text available via subscription   (Followers: 4)
Agricultural Systems     Hybrid Journal   (Followers: 22)
Agricultural Water Management     Hybrid Journal   (Followers: 19)
Agriculture     Open Access   (Followers: 7)
Agriculture & Food Security     Open Access   (Followers: 12)
Agriculture (Poľnohospodárstvo)     Open Access   (Followers: 1)
Agriculture and Agricultural Science Procedia     Full-text available via subscription   (Followers: 1)
Agriculture and Human Values     Hybrid Journal   (Followers: 12)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 36)
Agriprobe     Full-text available via subscription  
Agriscientia     Open Access  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 3)
Agro-Science     Full-text available via subscription  
Agroalimentaria     Open Access   (Followers: 1)
Agrociencia     Open Access   (Followers: 2)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 1)
Agronomía Colombiana     Open Access   (Followers: 1)
Agronomía Costarricense     Open Access   (Followers: 2)
Agronomía Mesoamericana     Open Access   (Followers: 1)
Agronomie Africaine     Full-text available via subscription  
Agronomy     Open Access   (Followers: 8)
Agrosearch     Open Access  
AI & Society     Hybrid Journal   (Followers: 3)
Alinteri Zirai Bilimler Dergisi : Alinteri Journal of Agricultural Sciences     Open Access  
Ambiência     Open Access  
Ambiente & Agua : An Interdisciplinary Journal of Applied Science     Open Access   (Followers: 1)
American Journal of Agricultural and Biological Sciences     Open Access   (Followers: 12)
American Journal of Botany     Full-text available via subscription   (Followers: 14)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 24)
American Journal of Potato Research     Hybrid Journal   (Followers: 2)
American Journal of Rural Development     Open Access   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Annales des Sciences Agronomiques     Full-text available via subscription  
Annals of Agricultural and Environmental Medicine     Open Access   (Followers: 1)
Annals of Agricultural Sciences     Open Access   (Followers: 1)
Annual Review of Resource Economics     Full-text available via subscription   (Followers: 11)
APCBEE Procedia     Partially Free   (Followers: 2)
Applied Economics Letters     Hybrid Journal   (Followers: 24)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 7)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 7)
Archivos de Zootecnia     Open Access   (Followers: 4)
Arquivos do Instituto Biológico     Open Access  
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1)
Asian Economic Papers     Hybrid Journal   (Followers: 3)
Asian Journal of Agricultural Research     Open Access   (Followers: 4)
Asian Journal of Plant Sciences     Open Access   (Followers: 2)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 6)
Australian Economic Review     Hybrid Journal   (Followers: 7)
Australian Forest Grower     Full-text available via subscription   (Followers: 2)
Australian Forestry     Full-text available via subscription   (Followers: 4)
Australian Grain     Full-text available via subscription   (Followers: 5)
Australian Holstein Journal     Full-text available via subscription   (Followers: 2)
Australian Journal of Agricultural and Resource Economics     Hybrid Journal   (Followers: 6)
Australian Journal of Agricultural Engineering     Open Access   (Followers: 1)
Australian Sugarcane     Full-text available via subscription  
Avances en Investigacion Agropecuaria     Open Access   (Followers: 1)
Bangladesh Journal of Agricultural Research     Open Access   (Followers: 3)
Bangladesh Journal of Scientific Research     Open Access   (Followers: 1)
Bioagro     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 5)
Biocontrol Science and Technology     Hybrid Journal   (Followers: 5)
Biodiversity     Hybrid Journal   (Followers: 25)
Biodiversity : Research and Conservation     Open Access   (Followers: 23)
Biological Agriculture & Horticulture : An International Journal for Sustainable Production Systems     Partially Free   (Followers: 11)
Biosystems Engineering     Hybrid Journal   (Followers: 1)
Biotemas     Open Access  

        1 2 3 4 5 | Last

Journal Cover   Biosystems Engineering
  [SJR: 0.773]   [H-I: 66]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1537-5110 - ISSN (Online) 1537-5129
   Published by Elsevier Homepage  [2800 journals]
  • Automatic classification of plants based on their leaves
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Aimen Aakif, Muhammad Faisal Khan
      The proposed algorithm identifies a plant in three distinct stages i) pre-processing ii) feature extraction iii) classification. Different leaf features, such as morphological features, Fourier descriptors and a newly proposed shape-defining feature, are extracted. These features become the input vector of the artificial neural network (ANN). The algorithm is trained with 817 samples of leaves from 14 different fruit trees and gives more than 96% accuracy. To verify the effectiveness of the algorithm, it has also been tested on Flavia and ICL datasets and it gives 96% accuracy on both the datasets.


      PubDate: 2015-08-30T07:00:36Z
       
  • Tracking oxygen and temperature dynamics in maize silage-novel application
           of a Clark oxygen electrode
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Yurui Sun, Menghua Li, Qiang Cheng, Kerstin H. Jungbluth, Christian Maack, Wolfgang Buescher, Daokun Ma, Haiyang Zhou, Hong Cheng
      Making silage involves a complicated biochemical process where oxygen (O2) is rapidly consumed within the sealed environment leading to fermentation and stable storage of the biomass. Reintroduction of the oxygen from a leak or the feed-out process results in silage degradation. Monitoring silage O2 concentration and temperature (T si) can provide critical insight regarding silage quality. Thus, an in situ biosensor for simultaneous monitoring of O2 and T si to track silage aerobic deterioration has long been needed but was unavailable. Although the Clark oxygen electrode (COE) is traditionally applied for O2 concentration dissolved in liquids, we extended its use to the gaseous phase of silage based on Henry's law. This study tested COE's using two trials, where trial-1 explored the initial-aerobic/ensiling phase and trial-2 examined the silage feed-out phase. The experimental results of both trials demonstrated that the COE can be an important monitoring tool for assessing the O2 dynamics throughout the silage lifecycle.


      PubDate: 2015-08-26T06:53:52Z
       
  • Measurement and analysis of ammonia, hydrogen sulphide and odour emissions
           from the cattle farming in Estonia
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Marek Maasikmets, Erik Teinemaa, Allan Kaasik, Veljo Kimmel
      Emissions from cattle farms in Estonia may vary from emissions in other regions of Europe due climatic differences and the housing systems used. Emission factors (EF) for the tie and loose housing systems for dairy farming were measured. Ammonia, odour and H2S emission measurements were made in tie and loose housing cattle farms with solid and liquid manure systems. Measurement were carried out in 2007 (10 different days from February to October) and in 2013 (in 30 different days in July–August). The gaseous EFs calculated for the tie housing cow building were 5.34 ± 0.47 kg [NH3] y−1 AU−1, 19.36 ± 4.39 g [H2S] y−1 AU−1 and for odour was 1.77 ± 3.06 OU y−1 AU−1. The EFs for the loose housing cow barn were 6.50 ± 4.01 kg [NH3] y−1 AU−1, 51.34 ± 30.34 g [H2S] y−1 AU−1 and for odour were 15.63 ± 20.96 OU y−1 AU−1. The NH3 and H2S EFs were validated through dispersion modelling against ambient levels measured in vicinity of the farms using passive samplers. An Eulerian advection-diffusion model with meteorological data was used to validate NH3 and H2S emission data. There was in general good correlation between measured and modelled levels for NH3 in both farms and for H2S in farm B. In general the EF were reliable and can be used in local and regional emission inventories and in dispersion calculations, but variation of emissions with temperature needs be taken into account. Further research is required to investigate emissions from more dairy farms over longer periods.


      PubDate: 2015-08-26T06:53:52Z
       
  • Influence of season and outdoor run characteristics on excretion behaviour
           of organic broilers and gaseous emissions
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Bertrand Méda, Mélynda Hassouna, Marcel Lecomte, Karine Germain, Jean-Yves Dourmad, Paul Robin
      Two organic broilers rearing systems, each associated with a broiler house of 75 m2 and an outdoor run of 2500 m2, were studied. In the first system, the outdoor run consisted of grassland (GRASS) but in the second, the outdoor run was planted with oaks (TREE). Two batches of broilers were studied from winter to spring (WS) and from summer to autumn (SA). Indoor and outdoor airborne concentrations of NH3, N2O, CH4, CO2 and H2O were measured using a photoacoustic infrared analyser. Air flow rate through the broiler house was estimated using SF6 tracer gas. The final amount and composition of the manure was determined. A mass balance was determined for N, P and water. Results showed that in SA, more nutrients were excreted in the outdoor run (41%) compared with WS (11%). During the WS season, outdoor excretion was greater in the TREE system but this was not observed during SA. Ammonia indoor emissions were higher during WS (200–283 mg [NH3] d−1 bird−1) than during SA (99–116 mg [NH3] d−1 bird−1). Total emissions from the systems (indoor + outdoor) were assessed using our values and data from the literature for outdoor emissions. This confirmed that total NH3 emissions were in the same range as emissions of broilers reared in closed houses. N2O emissions were higher during WS but represented less than 0.5% of indoor N excretion. Total CH4 emissions were very low (40–60 mg [CH4] d−1 bird−1), particularly in comparison with emissions in other species.


      PubDate: 2015-08-26T06:53:52Z
       
  • Sugar beet (Beta vulgaris L.) and thistle (Cirsium arvensis L.)
           discrimination based on field spectral data
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Francisco J. Garcia-Ruiz, Dvoralai Wulfsohn, Jesper Rasmussen
      Creeping thistle (Cirsium arvensis (L.) Scop.) is a perennial weed that causes yield loss in sugar beet (Beta vulgaris L.) crops. The weeds are usually mapped for site specific weed management because they tend to grow in patches. Remote sensing techniques have shown promising results in species discrimination and therefore provide potential for weed mapping. In this study we examined the feasibility of high-resolution imaging for sugar beet and thistle discrimination and proposed a protocol to select multispectral camera filters. Spectral samples from sugar beet and thistle were acquired with a field portable spectroradiometer under field conditions and Partial Least Squares Discriminant Analysis (PLS-DA) classification models were developed with 211 and 36 spectral features of 1.56 and 10 nm bandwidths, respectively. The classification rates obtained using these models were regarded as the maximum obtainable. Then, spectral responses of a multi-band camera equipped with the filter configuration proposed by the PLS-DA models were simulated. Finally, a simulation of crop-weed discrimination was made using small unmanned aerial vehicles (UAV)-based multispectral images. More than 95% of the thistles and 89% of the sugar beets were correctly classified when continuous spectral data were used with 1.56 and 10 nm bandwidths. Accuracy dropped to 93% of thistles identified and 84% of sugar beets correctly classified when only the four best bands were used. The validation based on aerial images showed that sugar beets and thistle plants could be discriminated in images if sufficient pure pixels containing leaf spectra were available, that is with spatial resolutions of 6 mm pixel−1 or finer.


      PubDate: 2015-08-26T06:53:52Z
       
  • Computer vision recognition of stem and calyx in apples using
           near-infrared linear-array structured light and 3D reconstruction
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Baohua Zhang, Wenqian Huang, Chaopeng Wang, Liang Gong, Chunjiang Zhao, Chengliang Liu, Danfeng Huang
      Automatic detection of common defects on apples by computer vision is still a challenge due to the similarity in appearance between true defects and stems/calyxes. Because the stem and calyx present a concave feature in apples, this paper proposes a novel stem and calyx recognition method using a computer vision system combined with near-infrared linear-array structured lighting and 3D reconstruction techniques to reveal this concavity. The 3D surface of the upper half of the inspected apples could be reconstructed by using a single multi-spectral camera and near-infrared linear-array structured light line by line on an adjustable speed conveyor belt. The height information for each pixel could be calculated by triangulation. Stems and calyxes would present a lower height than that of their neighbouring regions due to the local concave surface. In order to recognise the stems and calyxes efficiently, a standard spherical model (without stems and calyxes) is also constructed automatically, adapted to the size and boundary shape of the inspected apple. The difference between the 3D surface reconstruction and standard spherical model provides great potential for the recognition of stems and calyxes in apples. The final stem and calyx recognition algorithm was developed on the ratio images between 3D surface reconstruction images and standard spherical model construction images in gray level. The result had 97.5% overall recognition accuracy for the 100 samples (200 images), indicating that the proposed system and methods could be used for stem and calyx recognition.


      PubDate: 2015-08-26T06:53:52Z
       
  • The efficiency of shredded and briquetted wheat straw in anaerobic
           co-digestion with dairy cattle manure
    • Abstract: Publication date: November 2015
      Source:Biosystems Engineering, Volume 139
      Author(s): Cristiane A.N. Xavier, Verónica Moset, Radziah Wahid, Henrik B. Møller
      Anaerobic co-digestion of cattle manure (CM) with shredded or briquetted wheat straw (SS and BS, respectively) was evaluated in thermophilic continuously stirred tank reactors (CSTR) in two experiments (lab and full-scale). Three lab-scale CSTR (15 l) were used with 20 days hydraulic retention time (HRT); one was fed with CM and the other two with mixtures of CM (95% of fresh matter, FM) and SS or BS (5% FM). In the second experiment, two full-scale CSTR (30 m3) were operated with 25 days HRT; one reactor was fed with CM and the other with CM + BS (9% FM). Ultimate CH4 yield was analysed from each substrate. Biochemical CH4 potential at 21 days for CM, SS and BS were 128; 187 and 200 lSTP [CH4] kg−1 [VS]. Anaerobic digestion of CM, CM + SS and CM + BS in lab-scale reactors yielded 165; 214 and 217 lSTP [CH4] kg−1 [VS]. In full scale-reactors, CM and CM + BS yielded 264 and 351 lSTP [CH4] kg−1 [VS]. Increments of 31 and 33% on CH4 yield were achieved in CM + BS compared to CM in lab and full-scale reactors, respectively. Regarding the energy balance, the energy yields were the same for both reactors using straw as co-substrate (CM + SS and CM + BS) after subtracting the energy consumption of the pretreatment, corresponding to 1100 kWh of net energy output. However, briquetting technology could be advantageous for biogas plants where the straw might be transported over longer distances, due to reduction of the transportation costs.


      PubDate: 2015-08-26T06:53:52Z
       
  • Editorial Board
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137




      PubDate: 2015-08-14T07:55:59Z
       
  • Coverage planning for capacitated field operations, part II: Optimisation
    • Abstract: Publication date: Available online 6 August 2015
      Source:Biosystems Engineering
      Author(s): Martin F. Jensen, Dionysis Bochtis, Claus G. Sørensen
      Capacitated field operations refer to the operations that involve material flow where there are capacity constraints to the load that the machine is able to carry. A capacitated operation cannot therefore be completed in one operation and the machine has to interrupt the operation, leave the field and travel to an out-of-field facility for refilling (or unloading) and to return back to the field to resume the operation. This paper develops an algorithmic approach for the optimisation of capacitated field operations using the case of liquid fertilising. The approach is based on the state-space search technique where a solution is a sequence of pre-defined driving actions which are applied to the initial state that transform it to a goal state under the criterion of the minimisation of the non-productive travelled distance. In order to minimise the branching factor of the state-space search, the sequence of the working tracks is optimised in a post-process stage where the non-productive travelled distance in headland turnings is further minimised by implementing the travelling salesman problem methodology. In order to assess the improvements in the operations efficiency derived from the presented method, three fertilising operations were recorded and the optimised plans were compared to the conventional plans followed during the operations. Savings in the non-productive travelled distance was 15.7 %–43.5 %, while savings in the total travelled distance was 5.8 %–11.8 %.


      PubDate: 2015-08-09T00:26:25Z
       
  • Evaluation of the performance of field olfactometers by selected ion flow
           tube mass spectrometry
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Christophe Walgraeve, Katrijn Van Hufffel, Joren Bruneel, Herman Van Langenhove
      Odour quantification is generally performed by olfactometry, a technique which determines to what extent an odorous air sample should be diluted with odour-free air to be just distinguishable from odour-free air. In this study, the performance of two field olfactometers (Nasal Ranger and Scentroid 110c) was evaluated with respect to their ability to generate accurate dilutions. Therefore, an air stream with known concentrations (500 ppbv–5 ppmv) of odorous compounds (acetic acid, propanoic acid, n-butanol, dimethyl sulphide, dimethyl disulphide) was diluted by the olfactometers at their different set points after which the concentrations of the target compounds in the diluted air stream were measured by selected ion flow tube mass spectrometry (SIFT-MS). This enabled to determine the observed dilution ratios (DR obs ) and relate them to the set point values (DR set ). The Nasal Ranger showed good performance in the interval between DR set 3 and 31. Only at the highest set dilution ratio (DR set =61) breakthrough of the compounds through the activated carbon filter was observed. This breakthrough resulted in lower observed dilution ratios (up to a factor of 2 for dimethyl sulphide) when compared to the DR set . For the Scentroid a good linearity between DR set and DR obs was observed but dilution ratios were much higher (up to a factor of 2) than what could be theoretically expected on the basis of air flows. This behaviour could be explained by sorption effects of the target compounds onto the metal parts and into the rubber seal of the Scentroid.


      PubDate: 2015-08-09T00:26:25Z
       
  • Open source hardware to monitor environmental parameters in precision
           agriculture
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): F.J. Mesas-Carrascosa, D. Verdú Santano, J.E. Meroño, M. Sánchez de la Orden, A. García-Ferrer
      Precision agriculture combines the use of information and technology to ensure the best agricultural practices. Obtaining real-time non-invasive information to monitor crops or make yield predictions is a challenge. An approach is to use crop yield models in combination with real-time data used as input in such models. It was demonstrated that it is possible to design an accurate system using open source hardware and open systems to record the input for these models and monitor crops. The system presented has two main components: a device that records environmental parameters and a smartphone application (software) that links this device to a data server in order to process and analyse the information. The solution is scalable in terms of the type of sensors used (i.e. temperature and relative humidity of the air or soil), the rate of information retrieval and so on, so it can be used in various scenarios, including environmental or land policy monitoring. Moreover, this open source hardware can be used by a broad variety of users and is an alternative in poor rural areas because of its low cost compared to other solutions. It can enable increased agricultural production and management of the local environment, bringing new agricultural practices to these areas. Furthermore, progress in the use of this type of technology can help to develop new capabilities for growers. Results of calibration tests and measurements to demonstrate the usefulness of this system in precision agriculture are presented.


      PubDate: 2015-08-05T00:13:51Z
       
  • Detection of fungal infection in almond kernels using near-infrared
           reflectance spectroscopy
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Pei-Shih Liang, David C. Slaughter, Alejandro Ortega-Beltran, Themis J. Michailides
      Aspergillus flavus and Aspergillus parasiticus are ubiquitous in natural environments and have the potential to produce aflatoxins that can cause both chronic and acute diseases in humans and animals. The near-infrared (800–2500 nm) reflectance spectra of almonds from the 2012 and 2013 harvest seasons inoculated with one selected isolate of either A. flavus or A. parasiticus were analysed to determine if the spectra could be used to distinguish infected almonds from uninfected control almonds. A canonical classifier was developed that could discriminate infected almonds from the uninfected control kernels with a total cross-validation error rate of 0.26% and zero false negative errors. Additionally, a follow-up canonical classifier was developed to evaluate the potential to discriminate between infections by the two Aspergillus species, once infection was detected. Spectral analysis indicated that the NIR wavebands associated with lipid content were the most indicative factors in both identifying the infected almonds as well as discriminating between almonds infected by the A. flavus or the A. parasiticus isolate. Further comparison of the canonical discriminant analysis results from the 2nd derivative spectra and the original spectra also suggested that the chemical differences caused by the fungal metabolism had a much greater contribution to the discriminant function than the structural changes caused by the fungal invasion. The wavelengths identified in this study could be helpful in developing non-destructive multispectral sensing systems to effectively scan and detect almonds with fungal infection.


      PubDate: 2015-08-05T00:13:51Z
       
  • Pressure drop across sand and recycled glass media used in micro
           irrigation filters
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Josep Bové, Gerard Arbat, Miquel Duran-Ros, Toni Pujol, Joaquim Velayos, Francisco Ramírez de Cartagena, Jaume Puig-Bargués
      Filtration is necessary for avoiding emitter clogging in micro irrigation systems. The pressure drop across different granular media, such as silica sand, crushed recycled glass, surface modified glass and glass microspheres of selected grain sizes ranging from 0.63 to 1.50 mm, was studied in a laboratory filter scaled from a commercial filter using tap water. Real and bulk densities, porosity, sphericity and the equivalent diameter of these media were measured. The pressure loss was also measured at filter surface velocities from 0.004 to 0.025 m s−1. The pressure losses for the silica sand, crushed glass and modified glass were 39%, 27% and 10% lower than that for microspheres. The experimental results were compared with predicted values calculated using Ergun and Kozeny–Carman equations, as well as other multiple linear equations obtained with the stepwise methodology. Although the Ergun equation was the most accurate for predicting pressure drop, a newly developed equation that requires only grain size as the physical parameter of each medium also showed good performance and it may be of interest for use by irrigation engineers.


      PubDate: 2015-07-31T20:55:06Z
       
  • Coverage planning for capacitated field operations, Part I: Task
           decomposition
    • Abstract: Publication date: Available online 23 July 2015
      Source:Biosystems Engineering
      Author(s): Martin F. Jensen, Michael Nørremark, Patrizia Busato, Claus G. Sørensen, Dionysis Bochtis
      In certain field operations, such as fertilising, capacity restrictions lead to significant non-productive in-field travelling and out-of-field transport, thereby reducing field efficiency and increasing operating costs. This indicates a potential benefit from improving the efficiency of capacitated operations by minimising the non-productive travelled elements. A prerequisite for the optimisation of a field operation is the identification of the activities which contribute to the reduction of the efficiency and the definition of the actions that take place during the operation. The objective of this paper was to identify the sources of non-productivity in capacitated field operations and decompose the operation to feasible driving actions. Based on the monitoring of operations and subsequent data analysis, the recorded driven paths were decomposed into four types of non-productive activities. The involved driving actions during the fertilising operation were then defined, and finally, the potential of minimising the contribution of each non-productive activity to the operation efficiency by the selection of appropriate driving actions, was quantified. This assessment revealed that the selection of a subsequent action, might on one hand decrease the contribution of a specific non-productive activity to the total non-working travelled distance, but on the other hand might increase this contribution of another activity. There is therefore a trade-off between the positive contribution to the overall efficiency between one activity and the negative contribution from another. This indicates that a targeted algorithmic optimisation method should be devised by searching for the optimal combination among the prescribed driving actions.


      PubDate: 2015-07-24T09:42:48Z
       
  • Comparison of equipment used to measure shear properties in equine arena
           surfaces
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Kate Lewis, Alison J. Northrop, Glen M. Crook, John Mather, Jaime H. Martin, Danielle Holt, Hilary M. Clayton, Lars Roepstorff, Michael ‘Mick’ L. Peterson, Sarah J. Hobbs
      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°, 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.


      PubDate: 2015-07-20T09:36:17Z
       
  • Analysis of a motion planning problem for sweet-pepper harvesting in a
           dense obstacle environment
    • Abstract: Publication date: Available online 17 July 2015
      Source:Biosystems Engineering
      Author(s): C. Wouter Bac, Tim Roorda, Roi Reshef, Sigal Berman, Jochen Hemming, Eldert J. van Henten
      To reach a fruit in an obstacle-dense crop environment, robotic fruit harvesting requires a collision-free motion of the manipulator and end-effector. A novel two-part analysis was conducted of a sweet-pepper harvesting robot based on data of fruit (N = 158) and stem locations collected from a greenhouse. The first part of the analysis compared two methods of selecting the azimuth angle of the end-effector. The new ‘constrained-azimuth’ method avoided risky paths and achieved a motion planning success similar to the ‘full-azimuth’ method. In the second part, a sensitivity analysis was conducted for five parameters specifying the crop (stem spacing and fruit location), the robot (end-effector dimensions and robot position) and the planning algorithm, to evaluate their effect on successfully finding a collision-free goal configuration and path. Reducing end-effector dimensions and widening stem spacing are promising research directions because they significantly improved goal configuration success, from 63% to 84%. However, the fruit location at the stem is the strongest influencing parameter and therefore provides an incentive to train or breed plants that develop more fruit at the front side of the plant stem. The two analyses may serve as useful tools to study motion planning problems in a dense obstacle environment.


      PubDate: 2015-07-20T09:36:17Z
       
  • Effects of pretreatment conditions and post–pretreatment washing on
           ethanol production from dilute acid pretreated rice straw
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Christopher Lee, Yi Zheng, Jean S. VanderGheynst
      Rice straw pretreatment was examined in a full factorial study at temperatures of 120 °C and 160 °C and 0% and 1% [H2SO4]. Pretreatment efficacy was assessed by measuring hydrolysate composition and reducing sugar yield after enzymatic hydrolysis. Pretreatment with 1% [H2SO4] and 160 °C yielded the highest amount of reducing sugar, 259 mg g−1 [dry matter], during enzymatic hydrolysis corresponding to 57% glucose conversion based on cellulose content of the pretreated solid. Under this pretreatment condition hydroxymethylfurfural and furfural were 0.19 and 0.68 g l−1, respectively. Rice straw pretreated with 1% [H2SO4] at 160 °C was subjected to simultaneous saccharification and fermentation (SSF) using either Saccharomyces cerevisiae D5A or recombinant Escherichia coli KO11. Solid and hydrolysate separation and washing techniques were evaluated for their effect on ethanol production during SSF. Pretreated rice straw without liquid–solid separation or washing had the highest 7-d ethanol yield of 0.2 g [ethanol] g−1 [dry substrate] for E. coli KO11. This finding has economic implications on the processing of rice straw to bioethanol.


      PubDate: 2015-07-20T09:36:17Z
       
  • A smart mirror to promote a healthy lifestyle
    • Abstract: Publication date: Available online 14 July 2015
      Source:Biosystems Engineering
      Author(s): Sara Colantonio , Giuseppe Coppini , Danila Germanese , Daniela Giorgi , Massimo Magrini , Paolo Marraccini , Massimo Martinelli , Maria Aurora Morales , Maria Antonietta Pascali , Giovanni Raccichini , Marco Righi , Ovidio Salvetti
      ICT solutions to foster behavioural change have been shown to be effective in implementing primary prevention in terms of a healthy lifestyle. Primary prevention is the most viable approach to reduce the socio-economic burden of chronic and widespread diseases, such as cardiovascular and metabolic diseases. In this paper, we present a novel multisensory device, the Wize Mirror, which is under development in the EU FP7 Project SEMEOTICONS. The Wize Mirror detects and monitors over time semeiotic face signs related to cardio-metabolic risk, and encourages users to reduce their risk by improving their lifestyle.


      PubDate: 2015-07-16T09:00:07Z
       
  • Development of a simplified model for predicting the optimum lengths of
           drip irrigation laterals with coextruded cylindrical in-line emitters
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Huseyin Yurdem , Vedat Demir , Aysegul Mancuhan
      Accurate hydraulic design of laterals is one of the most important factors for ensuring water distribution uniformity in drip irrigation systems. In order to keep water distribution uniformity at an appropriate value, pressure and flow rate variations of emitters along a lateral should be within acceptable limits. This makes the determination of the optimum lateral lengths for drip irrigation systems necessary. The objective of this study was to develop a simplified empirical model able to predict the optimum lateral length to obtain uniform water distribution. The model developed is valid for a 16 mm nominal pipe diameter, with cylindrical co-extruded emitters and emitter spacing ranging from 0.2 m to 1 m. Optimum lateral length data was obtained from 26 different drip irrigation pipes. The model developed accounted for 98.3% of the variation in the optimum lateral lengths. The model was obtained by considering pipes with inside diameters ranging from 12.3 to 14.2 mm, emitter inside diameters ranging from 11.5 to 12.6 mm, emitter lengths ranging from 31.6 to 68.2 mm, emitter spacing ranging between 0.2 and 1.0 m, emitter discharges ranging from 1.75 to 4.30 l h−1, and emitter flow variations from 10 % to 20 %, with gradients extending downhill or uphill <3%. The errors in the optimum lateral lengths increased with 3% downhill gradients for 0.75 and 1.0 m emitter spacing. The prediction model can be used to calculate the optimum lateral lengths without using any software.


      PubDate: 2015-07-16T09:00:07Z
       
  • Automatic classification of respiratory patterns involving missing data
           imputation techniques
    • Abstract: Publication date: Available online 10 July 2015
      Source:Biosystems Engineering
      Author(s): Elena M. Hernández-Pereira , Diego Álvarez-Estévez , Vicente Moret-Bonillo
      A comparative study of the respiratory pattern classification task, involving five missing data imputation techniques and several machine learning algorithms is presented in this paper. The main goal was to find a classifier that achieves the best accuracy results using a scalable imputation method in comparison to the method used in a previous work of the authors. The results obtained show that in general, the Self-Organising Map imputation method allows non-tree based classifiers to achieve improvements over the rest of the imputation methods in terms of the classification accuracy, and that the Feedforward neural network and the Random Forest classifiers offer the best performance regardless of the imputation method used. The improvements in terms of accuracy over the previous work of the authors are limited but the Feed Forward neural network model achieves promising results.


      PubDate: 2015-07-12T08:49:51Z
       
  • Real-time characterisation of the harvesting process for adherent
           mesenchymal stem cell cultures based on on-line imaging and model-based
           monitoring
    • Abstract: Publication date: Available online 10 July 2015
      Source:Biosystems Engineering
      Author(s): Stefano Viazzi , Toon Lambrechts , Ioannis Papantoniou , Jan Schrooten , Jean-Marie Aerts
      Determining the optimal time to inhibit the enzymatic reaction during cell harvesting is crucial to successfully detaching adherent cells from the substrate before irreversible cell damage is caused by prolonged cell exposure to the enzymes. This study aimed at developing a non-invasive methodology to determine objectively and automatically the optimal time-point at which to inhibit the enzymatic reaction during cell harvesting. The harvesting process was monitored under a microscope and image analysis was used to measure the cells' morphology (circularity) from the images. System identification techniques were used to model the cells' circularity in response to the harvesting solution and to quantify the time when the cells become circular and reach a plateau phase (inhibition time). ARX models were used to accurately model the process both in culture flasks and in a bioreactor (R2 ≥ 0.98 and 0.95 respectively) and to quantitatively determine the inhibition time. First-order Recursive-ARX models were applied to predict the inhibition time in real-time. When the model parameters converged the median error was 21 s (Min 0 s, Max 75 s). The error decreased monotonically as new data were collected. The developed approach was generic and could be applied both in flasks and in a clinical-scale bioreactor. By automating decision-making, it will be possible to create standards and reproducibility that are necessary for large scale, robust and cost-effective cell cultures with reduced cell culture variability and consistent cell batches.


      PubDate: 2015-07-12T08:49:51Z
       
  • Understanding the lodging stability of green flax stems; The importance of
           morphology and fibre stiffness
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Marianne Gibaud , Alain Bourmaud , Christophe Baley
      Flax fibres (Linum usitatissimum) with good mechanical properties are required to reinforce polymers. Usually, their characterisation is made on retted and scutched fibres. This work provides a new and original method to both determine the stiffness of green fibres contained inside the plant and to estimate the crop lodging stability. We studied two recent flax varieties (Eden and Terre de Lin (TDL) 25) with a distinct lodging resistance (respectively high and low). Both varieties, grown under the same conditions, exhibit a similar fibre yield. The analysis conducted is based on the correlation between the bending stiffness of the stems, the distribution of fibres in a cross section and the properties of elementary flax fibres. The results of the mechanical characterisation indicate that the Eden variety has a superiority concerning fibre stiffness (68 GPa versus 55 GPa). The analysis of the bending stiffness of a dried plant at different localisations along the stem and of its fibre distribution in the corresponding cross section allowed us to estimate the fibres average modulus. Results obtained by this method were very close to the tensile tests values. The same procedure was used on green stems to approach the living state of the plant and to determine the Young's modulus of green fibres. The results highlighted a variation of fibre stiffness between the green state and the dried state (around +25%). The results enabled the use of a simplified buckling model, which confirmed the superiority of the Eden variety in lodging resistance. Thus, the analysis of the mechanical properties of flax stems and their structure could be a selection criterion.


      PubDate: 2015-07-12T08:49:51Z
       
  • Editorial Board
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136




      PubDate: 2015-07-12T08:49:51Z
       
  • A pilot scale electrical infrared dry-peeling system for tomatoes: Design
           and performance evaluation
    • Abstract: Publication date: September 2015
      Source:Biosystems Engineering, Volume 137
      Author(s): Zhongli Pan , Xuan Li , Ragab Khir , Hamed M. El-Mashad , Griffiths G. Atungulu , Tara H. McHugh , Michael Delwiche
      A pilot scale infrared dry-peeling system for tomatoes was designed and constructed. The system consisted of three major sections including the IR heating, vacuum, and pinch roller sections. The peeling performance of the system was examined under different operational conditions using tomatoes with different cultivars and sizes. Three lines of tomatoes were heated and processed at the same time at a residence time of 125 s and achieved a percentage of fully peeled tomatoes of 85%, a peeling yield of 82%, and an average thickness of peeled tomato skin of 0.75 mm. When tomatoes were loaded as a single line, the required heating time was reduced to a range from 80 to 100 s, depending of tomato size, for achieving the same level of peeling percentage and yield. The presence of the vacuum section could achieve cracks in 100% of the tomatoes after IR heating. The peeled products from IR heating had high firmness and appealing surface integrity, which indicated desirable quality characteristics. Because the dry-peeling is a chemical- and water-free process, residuals of tomato skins after IR peeling could be easily utilised as value-added by-products.


      PubDate: 2015-07-12T08:49:51Z
       
  • Early classification of parotid glands shrinkage in radiotherapy patients:
           A comparative study
    • Abstract: Publication date: Available online 4 July 2015
      Source:Biosystems Engineering
      Author(s): Marco Pota , Elisa Scalco , Giuseppe Sanguineti , Giovanni Mauro Cattaneo , Massimo Esposito , Giovanna Rizzo
      During radiotherapy treatment of patients with head-and-neck cancer, the possibility that parotid glands shrink was evidenced, connected with increasing risk of acute toxicity. In this ambit, the early identification of patients in danger is of primary importance, in order to treat them with adaptive therapy. This work studies different approaches for classifying parotid gland samples, taking into account textural features extracted from computed tomography (CT) images of monitored patients. A real dataset is used, and accuracy, sensitivity and specificity are counted as classification performances. Therefore, firstly, different procedures to define classes are compared in terms of their physical meaning and classification performances. Then, different methods for extracting knowledge from the dataset are implemented and compared in terms of performances and model interpretability. First-rate performance was obtained by using Likelihood-Fuzzy Analysis (LFA), which is a recently developing method based on the use of statistical information by means of Fuzzy Logic. The interpretable models extracted with LFA also allow identifying among textural features those able to predict parotid shrinkage. Some of these features are already known and are confirmed here, others are new, and some of them are very early predictors. Finally, an example of textural feature monitoring and classification of a patient is presented, through a reasoning scheme similar to human reasoning, based on the interpretation of simple rule-based models using linguistic variables.


      PubDate: 2015-07-12T08:49:51Z
       
  • Effect of soil type, peat, and compaction effort on soil strength and
           splash detachment rates
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Edwin I. Ekwue , Davindra Seepersad
      The effect of incorporation of peat into soils of diverse texture on soil strength and splash detachment rates during simulated rainfall was examined in the laboratory. Soil penetration resistance (an index of soil strength) and splash detachment by raindrops were measured on three soils (a sandy loam, a clay loam and the other clay) with peat added at 0, 4%, 8% and 12% (by mass), and pre-compacted at 159 kPa, 425 kPa and 638 kPa before being exposed to four rainfall durations of 4, 8, 12 and 20 min. The rainfall intensity was 92 mm h−1. Splash detachment increased with increasing rainfall duration with the largest values occurring in the sandy loam and the lowest in the clay loam soil. Soil penetration resistance initially increased up to 4 or 8 min of rainfall and then decreased as rainfall duration increased further. Splash detachment declined, while soil penetration resistance increased, with increasing compaction of the soil. Both parameters decreased with increasing peat content. Splash detachment rates declined with increasing rainfall duration, with the maximum reduction occurring in soils with low peat contents, low compaction levels and high sand content. An equation was derived to relate splash detachment rates of the three soils to the product of soil penetration resistance and duration of rainfall.


      PubDate: 2015-06-26T19:18:25Z
       
  • Calibration of infiltration, roughness and longitudinal dispersivity
           coefficients in furrow fertigation using inverse modelling with a genetic
           algorithm
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Amir Sedaghatdoost , Hamed Ebrahimian
      Determining soil hydraulic properties in surface irrigation which the soil surface is used both to convey and infiltrate water is very important. It becomes an issue of great concern when fertilisers were also added to irrigation water during fertigation. The purpose of this study was to estimate infiltration, roughness and longitudinal dispersivity coefficients in conventional and alternate furrow fertigation using inverse modelling with a genetic algorithm. A surface fertigation model was used to simulate overland water flow and solute transport. To discover optimum values of the coefficients, a genetic algorithm with fifteen objective functions were used to minimise the differences between observed and simulated values of advance time, recession time, runoff hydrograph and runoff nitrate concentration. The results indicated that the infiltration, roughness and fertiliser dispersivity parameters were more sensitive to runoff, recession time and runoff nitrate concentration, respectively. The best simulations of advance and recession phases were obtained by the coefficients which were estimated from objective function that minimised the differences between observed and simulated values of advance and recession time, respectively. For improving simulation of runoff discharge, minimising the differences between observed and simulated values of runoff hydrograph as well as advance time was necessary. Similarly, the improved simulation of runoff nitrate concentration needed minimising differences between simulated and measured values of both advance and runoff nitrate concentration. The proposed inverse modelling approach with GA resulted in better performance as compared to the two-point method, particularly in fixed and variable alternate furrow fertigation.


      PubDate: 2015-06-26T19:18:25Z
       
  • Pose estimation-dependent identification method for field moth images
           using deep learning architecture
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Chenglu Wen , Daoxi Wu , Huosheng Hu , Wei Pan
      Due to the varieties of moth poses and cluttered background, traditional methods for automated identification of on-trap moths suffer problems of incomplete feature extraction and misidentification. A novel pose estimation-dependent automated identification method using deep learning architecture is proposed in this paper for on-trap field moth sample images. To deal with cluttered background and uneven illumination, two-level automated moth segmentation was created for separating moth sample images from each trap image. Moth pose was then estimated in terms of either top view or side view. Suitable combinations of texture, colour, shape and local features were extracted for further moth description. Finally, the improved pyramidal stacked de-noising auto-encoder (IpSDAE) architecture was proposed to build a deep neural network for moth identification. The experimental results on 762 field moth samples by 10-fold cross-validation achieved a good identification accuracy of 96.9%, and indicated that the deployment of the proposed pose estimation process is effective for automated moth identification.


      PubDate: 2015-06-26T19:18:25Z
       
  • Surface renewal and eddy covariance measurements of sensible and latent
           heat fluxes of cotton during two growing seasons
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Rafael Rosa , Josef Tanny
      Measuring evapotranspiration (ET) of agricultural crops is crucial for accurate irrigation and efficient water management. The surface renewal (SR) technique, which relies on high-frequency measurements of air temperature by a miniature sensor, is a simple technique for estimating ET. Sensible heat flux is estimated from the temperature-time series and evapotranspiration is deduced from the energy-balance closure. We examined the use of the SR technique for cotton, for the first time. Field experiments were carried out at the same site during two consecutive summers, with an eddy covariance (EC) system used for calibration of the surface-renewal weighting factor. Regressions between sensible heat flux values as measured by EC and SR, yielded coefficients of determination of up to 0.86. The SR weighting factor decreased with increasing height but above the canopy top this decrease was small. The ratio between weighting factors obtained during the two years depended strongly on the temperature sensor quality; for the ultrasonic anemometer with a high-frequency response a mean ratio of 0.90 ± 0.06 was obtained. A maximum deviation of 7% was found between daily ET obtained by EC and SR methods during validation. Reducing the frequency of data analysis from the commonly used 10 Hz down to 1 Hz, increased the weighting factor but did not much affect the ET results, which indicates that the SR technique could be realised by using low-cost data acquisition systems.


      PubDate: 2015-06-26T19:18:25Z
       
  • Field assessment of basin irrigation performance and water saving in
           Hetao, Yellow River basin: Issues to support irrigation systems
           modernisation
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Qingfeng Miao , Haibin Shi , José M. Gonçalves , Luis S. Pereira
      Water-saving irrigation needs to be implemented in Hetao irrigation district to help satisfying the demand by other users in the Yellow River basin. Aiming at assessing the potential irrigation performance and water saving at farm level, a set of traditional basins and another of precision-levelled basins cropped with maize, wheat and sunflower and managed by farmers were evaluated. Data were collected to characterise the basin sizes, microtopography, inflow rates, advance and recession times, cut-off time and soil water content. In addition, families of infiltration curves were derived from field observations and subsequent use of model SIRMOD. Infiltration was higher for the precision-levelled basins and decreased from the first to the next irrigation events. Infiltration data were used to support the computation of distribution uniformity (DU), beneficial water use fraction (BWUF) and deep percolation (DP). For traditional basins, DU and BWUF were low and DP was high. When precise land levelling was practised, DU increased greatly to near 94% but BWUF improved little, because irrigation scheduling was inadequate leading to excessive water application; however, non-negligible water saving was achieved for maize and wheat since they have higher irrigation demand. In contrast, simulating the application of an appropriate irrigation scheduling through adjusting the cut-off time led to an approximately unchanged DU but BWUF greatly increased and DP reduced to 10% on average. This condition represents a potential water saving of 34–39%; however its achievement requires improved design of farm systems, appropriate irrigation water deliveries and scheduling, and the support and training of farmers.


      PubDate: 2015-06-26T19:18:25Z
       
  • Coupled moment analysis of stacked counter-rotating eccentric-mass tree
           shaker energy-wheel system
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Lloyd D. Snell , Stuart J. Birrell
      This paper expands the historical “Planar model” equation for inertial tree shakers using stacked counter-rotating eccentric-mass energy-wheels and accounts for coupled moments using a “Planar Force and Moment Model”. The energy-wheel configuration utilised by many tree shakers creates planar forces and coupled moment maxima and minima. When the centrifugal acceleration force vectors of each energy-wheel are aligned, this creates a force maximum, acting radially about the tree. The stacked energy-wheels assembly produces a coupled moment due to the centrifugal acceleration force vectors acting on a lever arm. The lever arm vectors extend from a coordinate system coincident with the shaft centre line, and between the upper and lower energy-wheels centre of gravity. A coupled moment maximum occurs when the energy-wheel force vectors are opposing, the planar force is a minimum. The shaker head will roll, pitch, and yaw about the tree trunk due to the instantaneous coupled moment. The rotational and non-normal planar forces are more likely to cause tree trunk bark injury. Subsystems, such as lubricated pads and slings, are required to mitigate transmission of damaging forces. The Planar Force and Coupled Moment Model identifies the force causing vertical tree displacement. Though the Planar model shows that the timing of the energy-wheels produces the observed bi-directional pattern of force maxima, addition of the Coupled Moment shows that timing cannot eliminate non-normal forces. The new model provides a more complete representation of forces applied to the tree and could be used to optimise design for reduced tree damage.


      PubDate: 2015-06-26T19:18:25Z
       
  • Mathematical modelling of thin-layer drying according to particle size
           distribution in crushed feed rice
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Fumina Tanaka , Fumihiko Tanaka , Ai Tanaka , Toshitaka Uchino
      A thin-layer drying model taking into account the particle size distribution of crushed feed rice was developed to simulate moisture content during high-temperature drying. The model was based on the Page equation, which was regarded as a suitable empirical equation to describe the thin-layer drying of rice. The proposed model, with an assumed a Rosin–Rammler distribution, successfully predicted the mean moisture content of rice during drying experiments with a mean error of 0.5% dry basis at 60, 70, and 80 °C. In order to investigate the effect of particle size distribution of rice on the drying process, a stochastic model based on Monte Carlo simulations was developed. The model developed here could provide useful information on the drying behaviour of rice particles, individually and collectively, in a thin layer bed. It was clear that uniform drying could be achieved by increasing the drying temperature.


      PubDate: 2015-06-26T19:18:25Z
       
  • Comparison of leaf surface roughness analysis methods by sensitivity to
           noise analysis
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Houda Bediaf , Rachid Sabre , Ludovic Journaux , Frédéric Cointault
      Surface roughness is of great interest in agricultural spraying because it is used to characterise leaf surface wettability to predict the behaviour of droplets on a leaf surface. In recent years, the use of texture analysis to estimate surface roughness has emerged. In this paper we propose to estimate leaf surface roughness by using an optimisation of the Generalized Fourier Descriptors method. This approach is then compared with two other standard methods in the literature, one based on grey level intensity variation and the other on wavelet decomposition. Since roughness has many definitions and each method is calculated differently, we propose a new approach to compare the results based on the sensitivity of each method according to surface roughness variations. These variations were introduced by adding different kinds of noise to the image. Gaussian and salt & pepper noise are added to simulate rapid changes and peak impulses on the surface topography, whereas a Structural noise (sinusoidal signal) is added to simulate depth on the surface topography. The novelty of this contribution is the use of a new approach and procedure for agronomic application (leaf surface roughness). The results obtained are expected to be used to characterise the adhesion mechanisms of liquid droplets on a leaf surface.


      PubDate: 2015-06-26T19:18:25Z
       
  • Band spreader for the application of slurry solid fractions to orchards
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Paolo Balsari , Elio Dinuccio , Fabrizio Gioelli , Gianfranco Airoldi
      Mechanical separation of pig slurry is widely used in the Piedmont region of northwest Italy, where it is considered a reliable technique to reduce livestock nutrient load on farms. Transport of solid slurry fractions to areas of low animal density, such as where cereals and fruit trees are grown, is considered straightforward. However, because equipment specifically designed to distribute the solid fraction of slurries in orchards was not available a prototype spreader was developed. The machine, with a 4.5 m3 volume hopper, included a chain conveyor metring device and hydraulically-driven spinning plate so that the working width can be adapted to tree row space and shape differences enabling its use in a variety of operating conditions and orchard types. To ensure application of solid fraction was in compliance with crop requirements and regulations, the spreader was equipped with an electronic rate control system enabling target nutrient rates ranging from 10 to 120 kg [N] ha−1. It was tested for longitudinal and transverse distribution at different application rates and forward speeds. Test results showed that the control system maintained suitably even distribution patterns and steady application rates regardless of forward speed.


      PubDate: 2015-06-26T19:18:25Z
       
  • Computational fluid dynamics analysis of the thermal distribution of
           animal occupied zones using the jet-drop-distance concept in a
           mechanically ventilated broiler house
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Kyeong-seok Kwon , In-bok Lee , G. Qiang Zhang , Taehwan Ha
      Controlling airflow trajectory through slot-openings is important to induce an efficient thermal exchange in a broiler house, particularly in winter. A jet-drop-distance model was proposed to establish a plan for the control and management of a cold jet trajectory by Zhang & Strom (1999), Transactions of the ASAE, 42(4), 1121–1126. Jet-drop-distance is defined as the horizontal distance from a wall to an animal occupied zone where the incoming cold air first reaches at. Regression models employing jet-drop-factor and corrected Archimedes number variables were calculated based on experimental data. However, this approach was restricted, because of the small-scale model, the small number of slot-openings and difficulties in measuring invisible airflows being observed. Here, computational fluid dynamics (CFD) was adopted to overcome the experimental limitations and to analyse jet-drop-distances qualitatively and quantitatively in a commercial broiler house with multiple slot-openings. Predictions of jet-drop-distances were computed using the experimental conditions used by Zhang & Strom (1999) and compared with their regression models to validate the accuracy of developed method. In the validation test, the regression model using the corrected Archimedes number more accurately predicted the jet-drop-distance in the simulation model (R2 = 0.90). The validated method was subsequently applied to the analysis of the jet-drop-distance in a mechanically ventilated broiler house with multiple slot-openings. Trends of the CFD computed jet-drop-distance were analysed according to such variables as ventilation rate, initial angle of slot-openings and outdoor air temperature.


      PubDate: 2015-06-26T19:18:25Z
       
  • Design and test of an artificial reference cow to simulate methane release
           through exhalation
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Liansun Wu , Peter W.G. Groot Koerkamp , Nico W.M. Ogink
      To mitigate methane emission from dairy cows, a technique is needed to evaluate individual methane emission from a large number of cows under practical conditions in barns. For developing such a measurement technique, a known reference source that can simulate cow exhalation of methane would be a powerful tool to improve and validate measurement methods. The objective of this research was to design, construct, and test an artificial reference cow (ARC). We built a device that simulated exhaling and inhaling cycles and eructation. The ARC consisted of a cylinder in which methane was injected by mass flow controllers and ejected by a piston in the cylinder. The methane mass balance of the ARC, defined as the difference between the mass controllers imposed input and measured output, was tested under three settings. Methane concentration release patterns produced by five simulated cows were compared to patterns measured from real cows. Average methane concentration in exhaled gas had a mean difference of 2.8% between measured and predicted results. The output methane mass was strongly linearly related to the input methane mass. Methane concentration release patterns produced by the five simulated cows had a sinusoidal curve with similar time interval and comparable methane concentration level as real cows. It is concluded that the ARC properly represented the methane production release, and that the system precisely controlled methane concentration and production. The ARC can be used as a known reference source to develop practical methane measurement methods.


      PubDate: 2015-06-26T19:18:25Z
       
  • Modelling heat and mass transfer of a broiler house using computational
           fluid dynamics
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Fernando Rojano , Pierre-Emmanuel Bournet , Melynda Hassouna , Paul Robin , Murat Kacira , Christopher Y. Choi
      Improvements to the living conditions in semi-enclosed spaces such as broiler houses can be achieved by better control of the heat and mass transport that occur in climate and air quality. This study shows that computer-aided modelling, and in particular computational fluid dynamics (CFD), can provide to researchers the ability to integrate the primary forces that interact at the interior environment. A two dimensional CFD model was used to assess the dynamics of a broiler house by investigating sensible and latent heat, as well as mass transport and radiative transfer energy, as these relate to the environment of the broiler house. Validation data related to temperature, absolute humidity and CO2 were collected both inside and outside of a naturally ventilated broiler house. Inside data was logged at various locations to identify the degree of homogeneity throughout space. The CFD model replicated two contrasting cases: an early stage and a late stage of production. The predicted values for temperature, absolute humidity and CO2 were in good agreement with experimental data. For instance, the first case had a ventilation rate of 10 air changes h−1, and obtained a root-mean-square error (RMSE) of 1.0 °C, 0.3 g [H2O] kg−1 [dry air] and 134 ppm for temperature, absolute humidity and CO2, respectively. The second case had ventilation rates of 25 air changes h−1, and obtained a RMSE of 0.9 °C and 0.48 g [H2O] kg−1 [dry air] for temperature and absolute humidity, respectively.


      PubDate: 2015-06-26T19:18:25Z
       
  • Semi-mechanistic modelling of ammonia absorption in an acid spray wet
           scrubber based on mass balance
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Lara Jane S. Hadlocon , Lingying Zhao , Barbara E. Wyslouzil , Heping Zhu
      A model to describe reactive absorption of ammonia (NH3) in an acid spray scrubber was developed as a function of the combined overall mass transfer coefficient Kyav. An experimental study of NH3 absorption using 1% dilute sulphuric acid was carried out under different operating conditions. An empirical correlation for Kyav with respect to droplet Sauter mean diameter, liquid flow rate, and inlet NH3 concentration was developed with an R2 = 97.12%. Air velocity positively correlated with Kyav at 30 ppmv, but did not exhibit an effect at higher concentrations (165–300 ppmv), while liquid flow rate showed the greatest effect on Kyav. The Kyav correlation was incorporated in the performance model to construct a semi-mechanistic model with high prediction accuracy (R2 = 97.60%, MSE = 0, RMSE = 0.03, MAPE = 5.24%). This generalised performance model can be used to predict NH3 removal efficiencies of our optimised acid spray scrubber under various operating conditions at animal facilities.


      PubDate: 2015-06-26T19:18:25Z
       
  • Effect of compression speed on energy requirement and oil yield of
           Jatropha curcas L. bulk seeds under linear compression
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Abraham Kabutey , David Herák , Rostislav Chotěborský , Riswanti Sigalingging , Čestmír Mizera
      The influence of pressing speed on energy demand and percentage oil yield of Jatropha curcas L. bulk seeds was examined in compression loading test using Universal Testing Machine and vessel diameter of 60 mm. Maximum force of 100 kN and speed between 1 and 50 mm min−1 were applied on jatropha bulk seeds of initial moisture content 8.61% ± 1.14% (w. b.) at pressing height of 60 mm. The mechanical behaviour and deformation characteristic curves of jatropha bulk seeds were also assessed in relation to speed. Based on the statistical analysis of results, deformation energy decreased significantly (p < 0.05) with increasing speed from 0.43 ± 0.01 to 0.41 ± 0.01 kJ and oil yield from 19.05 ± 1.16 to 11.66 ± 0.82 (%) while slight decreases in maximum deformation from 45.02 ± 0.29 to 43.38 ± 2.63 (mm) were not statistically significant (p > 0.05). In contrast, oil point force increased with increasing compression speed from 17.03 ± 2.33 to 59.27 ± 30.81 kN, oil point deformation from 38.22 ± 0.49 to 41.99 ± 1.40 mm and oil point energy from 0.15 ± 0.01 to 0.31 ± 0.09 kJ, all significant at p < 0.05. The dependency between force and deformation curves of jatropha bulk seeds as function of speed did not exhibit any serration effect. The present study provides preliminary result that can support the incorporation of the speed variable into the already published tangent curve mathematical model, which can represent mechanical and deformation behaviour of bulk oilseeds under compression loading.


      PubDate: 2015-06-26T19:18:25Z
       
  • Permitted working hours with a motorised backpack sprayer
    • Abstract: Publication date: August 2015
      Source:Biosystems Engineering, Volume 136
      Author(s): Ahmad Kouchakzadeh , Yasan Beigzadeh
      Small-scale farmers often use motorised backpack sprayers to apply chemicals to crops. However, vibration from their internal combustion engines and other motive parts, such as pumps, is transmitted to the operator's body and this could cause harm. Vibration signals from a motorised backpack sprayer were measured using 3-axis accelerometers attached to the frame of the sprayer and the operator's wrist, chest, head and neck. The results from fast Fourier transform analysis showed a peak in horizontal vibrations of 3 m s−2 at a frequency of 20 Hz. According to ISO-2631-1 standard, this outcome signifies that the maximum continuous working time for practical use for the sprayer under test should therefore not exceed 1 h.


      PubDate: 2015-06-26T19:18:25Z
       
  • Corrigendum to “Evaluation and stability comparison of different
           vehicle configurations for robotic agricultural operations on
           side-slopes” [Biosystems Engineering 129 (2015) 197–211]
    • Abstract: Publication date: Available online 18 June 2015
      Source:Biosystems Engineering
      Author(s): Renato Vidoni , Marco Bietresato , Alessandro Gasparetto , Fabrizio Mazzetto



      PubDate: 2015-06-26T19:18:25Z
       
  • Classification of contaminants from wheat using near-infrared
           hyperspectral imaging
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Lankapalli Ravikanth , Chandra B. Singh , Digvir S. Jayas , Noel D.G. White
      Cereal grains are an important part of human diet; hence, there is a need to maintain high quality in these grains. Contaminants (foreign materials, dockage, and animal excreta) are the major impurities in cereal grains. A procedure was developed to differentiate these contaminants from wheat using near-infrared (NIR) hyperspectral imaging. Three experiments were conducted to identify the best combinations of spectral pre-processing technique and statistical classifier to classify contaminants represented by seven foreign material types (barley, canola, maize, flaxseed, oats, rye, and soybean); six dockage types (broken wheat kernels, buckwheat, chaff, wheat spikelets, stones, and wild oats); and two animal excreta types (deer and rabbit droppings) from Canada Western Red Spring (CWRS) wheat. The raw NIR reflectance spectra of these contaminants and wheat were collected in the NIR range (1000–1600 nm). These spectra were processed using five spectral pre-processing techniques (first derivative, second derivative, Savitzky-Golay (SG) smoothing and differentiation, multiplicative scatter correction (MSC), and standard normal variate (SNV)) to reduce signal noises and improve the generalised capability of statistical classifiers. The raw and pre-processed data were classified using Support Vector Machines (SVM), Naïve Bayes (NB), and k-nearest neighbours (k-NN) classifiers. In each study, two-way classifications were conducted to understand the classification of each contaminant type from wheat and multi-way classifications were conducted to understand the classification of all contaminant types from wheat. Contaminants and wheat were classified with highest classification accuracy when spectral data were pre-processed using the SNV technique and classified using the k-NN classifier.


      PubDate: 2015-06-26T19:18:25Z
       
  • Optimal reservoir capacity for centre pivot irrigation water supply: Maize
           cultivation in Spain
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): A. Izquiel , P. Carrión , J.M. Tarjuelo , M.A. Moreno
      Centre pivots are one of the most widespread irrigation systems in the world. The aim was to develop a tool to optimise the design and management of the water distribution and centre pivot systems seeking to minimise water application cost per unit area (C T ), including investment (C a ), operation (C e ), and maintenance costs. With this aim, two options were considered: to feed the centre pivot 1) directly from an aquifer or 2) using a regulation reservoir. A software tool DEPIRE (design of centre pivot with regulating reservoir), was developed and implemented in MATLAB 2012b (The MathWorks Inc., Natick, MA, USA). It determines optimal flows, pipe diameters, pumps power and the volume of the regulation reservoir for any crop water requirement, different electricity rates and water availability in the tube well. With this tool, the effect of the irrigated area (S), dynamic water level (DWL) in the aquifer and the pumping flow rate on the C T was evaluated for a maize crop in Spain. The study area representing the minor C T was 70 ha for direct pumping from the borehole and 100 ha when using an intermediate reservoir. Incorporating a regulation reservoir generates lower C T than direct feed from the borehole for S > 100 ha for any DWL. C T increased linearly with the DWL due to a significant increase in C e which primarily affects the cost of water extraction from the aquifer, with a smaller effect on the application cost of the irrigation system.


      PubDate: 2015-06-26T19:18:25Z
       
  • Multi-object extraction from topview group-housed pig images based on
           adaptive partitioning and multilevel thresholding segmentation
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Yi-zheng Guo , Wei-xing Zhu , Peng-peng Jiao , Chang-hua Ma , Jian-jun Yang
      The aim of this study is to provide a feasible method that can accurately extract individual pigs from a drinker and feeder zone; therefore, an object extraction method based on adaptive partitioning and multilevel thresholding segmentation is proposed. First, a single frame image is enhanced using histogram equalisation, and then it is segmented with a maximum entropy global threshold. The initial segmentation objects are obtained by extracting a “valid area” and morphological processing. Then, each object centroid is calculated from the initially segmented objects, and the original image is adaptively divided into multiple circular sub-blocks whose origin is the centroid and radius is the maximum distance from the centroid to the edge point. Finally, an accurate secondary segmentation result is obtained using multilevel thresholding segmentation in each sub-block. The test data included thirty random videos collected in AVI format, and 9000 frames from 5 days × 6 videos × 120 s × 25 frames s−1 were selected. Results show that the average detection rate is 92.5%. This paper also analyses the possible applications of the proposed method to pig behaviour analysis, individual recognition, and weight estimation.


      PubDate: 2015-06-26T19:18:25Z
       
  • Novel approach to evaluate the dynamic variation of wind drift and
           evaporation losses under moving irrigation systems
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Sayed-Hossein Sadeghi , Troy R. Peters , Mohammad Z. Amini , Sparkle L. Malone , Hank W. Loescher
      The increased need for water and food security requires the development of new approaches to save water through irrigation management strategies, particularly for center pivot irrigation. To do so entails monitoring of the dynamic variation in wind drift and evaporation losses (WDELs) of irrigation systems under different weather conditions and for relatively long time periods. The historical catch can method has limited our ability to address this goal. Here, a new and easy-to implement methodology, called the strip test, was developed and validated against the catch can technique. Our results showed strong agreement between the catch can method and the strip test for determining the average water application efficiency (WAE ≈ 1-WDEL). Because the strip test method was measured for shorter intervals compared to the catch can method, the variables influencing WAE were able to be compared during each test. WAE had a large variance over time, which was controlled, in part, by wind speed (>4 m s−1). Site-specific characterisation of WDEL is needed to apply this technique. Once applied, it can provide a better understanding of WAE behaviour over the time, and enhance the capability of predicting results for the optimising water use in sprinkler irrigation.


      PubDate: 2015-06-26T19:18:25Z
       
  • Towards real-time control of chicken activity in a ventilated
           chamber
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Ali Youssef , Vasileios Exadaktylos , Daniel A. Berckmans
      Monitoring and controlling some behavioural responses such as the activity level and position of broiler chickens in broiler houses could provide an inexpensive tool with the potential to improve broiler welfare, health, energy consumption and product quality. The main objective of this paper is to examine the possibility of controlling chickens' activity level and position in a small chamber via controlling the surrounding micro-environment. A small ventilated test chamber was used. In this study real-time modelling was used to predict the dynamic activity index of broilers in relation to variations in the inlet temperature and ventilation rate. Step inputs in both ventilation rate and inlet air temperature were applied and temperature at 30 sensor locations was recorded. The chamber was populated with 9 chickens (age 7 days). A digital CCD camera that was mounted on the top of the chamber was used to capture the birds' positions and motion. Images were captured with a resolution of 640 by 480 pixels at a 1 Hz frame rate. The airflow pattern inside the chamber was investigated by conducting a set of smoke experiments. Software was developed to calculate the activity level of all chickens in real-time. The dynamic variation of activity index of chickens was compared to the two-dimensional spatial profile of temperature and the airflow pattern inside the chamber. Real-time models are defined to describe the dynamic responses of the chickens' activity to changes in the micro-environmental temperature. The resulting models are the basis for a model-based predictive controller of chickens' activity. The mathematical basis for a model-based predictive control system is defined in this paper.


      PubDate: 2015-06-26T19:18:25Z
       
  • Improving in vivo plant nitrogen content estimates from digital
           images: Trueness and precision of a new approach as compared to other
           methods and commercial devices
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Roberto Confalonieri , Livia Paleari , Ermes Movedi , Valentina Pagani , Francesca Orlando , Marco Foi , Michela Barbieri , Michele Pesenti , Oliver Cairati , Marco S. La Sala , Riccardo Besana , Sara Minoli , Eleonora Bellocchio , Silvia Croci , Silvia Mocchi , Francesca Lampugnani , Alberto Lubatti , Andrea Quarteroni , Daniele De Min , Alessandro Signorelli , Alessandro Ferri , Giordano Ruggeri , Simone Locatelli , Matteo Bertoglio , Paolo Dominoni , Stefano Bocchi , Gian Attilio Sacchi , Marco Acutis
      Operational tools to support nitrogen (N) management in cropping systems are increasingly needed to maximise profit, minimise environmental impact, and to cope with market requirements. In this study, a new method (18%-grey DGCI) for estimating leaf and plant N content from digital photography was evaluated and compared with others based on image processing (DGCI and Corrected DGCI) and with commercial tools (leaf colour chart, SPAD-502, and Dualex 4). All methods were evaluated for rice using data collected in northern Italy in 2013, by adapting the ISO 5725-2 validation protocol. 18%-grey DGCI was further validated on independent data collected in 2014. Dualex achieved the best performances for trueness (R2 = 0.96 and 0.92 for leaf and plant N contents), although it presented partly unsatisfying values for precision (12.33% for repeatability and 14.81% for reproducibility). SPAD, instead, demonstrated the highest precision (repeatability = 4.51%, reproducibility = 4.98%), even if it was ranked third for trueness (R2 = 0.82 and 0.81 for leaf and plant N contents). 18%-grey DGCI was ranked second for trueness (R2 = 0.83 for both leaf and plant N contents) and third for precision (11.11% and 14.47% for repeatability and reproducibility). The good performances of the new method were confirmed during the 2014 experiment (R2 = 0.87 for leaf N content). The 18%-grey DGCI method has been implemented in a smartphone app (PocketN) to provide farmers and technicians with a low-cost diagnostic tool for supporting N management at field level in contexts characterised by low availability of resources.


      PubDate: 2015-06-26T19:18:25Z
       
  • Performance of controlled atmosphere/heating block systems for assessing
           insect thermotolerance
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Wei Li , Long Chen , Kun Wang , Judy A. Johnson , Shaojin Wang
      Heated controlled atmosphere (CA) treatments have potential as alternatives to chemical fumigation for disinfesting postharvest fresh and stored products. To determine accurately the minimal thermal requirements to kill target insects over a wide range of temperatures and CA conditions, it is desirable to develop a model system to assess quickly the target insect thermotolerance. This study evaluated the gas tightness of the new controlled atmosphere/heating block system (CA–HBS) and the stability of gas concentrations, and determined temperature variations in the treatment chamber with and without added gas and under different gas channel designs and heating rates. The results showed that the new CA–HBS had a relatively constant leakage rate and kept O2 and CO2 concentration variations to within ±0.067% and ±0.167% at three set points (1% O2:15% CO2, 2% O2:17% CO2, and 2% O2:20% CO2), resulting in relatively stable gas compositions. With the long gas channel design, temperature variations in the treatment chamber were not influenced by the addition of gas or by heating rates. The performance of the CA–HBS indicated that this model system could be used for rapid assessment of pest thermotolerance.


      PubDate: 2015-06-26T19:18:25Z
       
  • Machine function integration and its effect on the performance of a timber
           yarding and processing operation
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Bruce Talbot , Karl Stampfer , Rien Visser
      An assessment of the benefits of a fully integrated yarder-processor was made against the alternative of splitting the yarding and processing functions onto two base machines. The effect of productivity rates, specific costs, and crew sizes on the relative performance of each working configuration was investigated. The systems analysis showed that for the integrated yarder machine, a two-man crew was considerably cheaper than a three-man crew at all yarding distances, although the difference became less pronounced with increasing mean tree volumes. The single integrated machine with a 2-man crew was cheaper than the modelled 2-machine system at medium and longer extraction distances, as the processor base machine in the 2-machine systems incurred a considerable cost penalty in waiting idly for the yarder. At shorter distances (75 m) the 2-machine system was cheapest, but became less competitive with increasing mean tree volume. For mid-sized trees (0.38 m3) on a medium corridor length of 150 m, overall system productivity rates ranged from 5.2 m3 per productive system hour (PSH) for the single machine system to 9.4 PSH−1 for the 2-machine system, although the specific net costs were almost identical at 31.5 € m−3. A sensitivity analysis showed that reduced labour costs would promote use of the 2-machine system, suggesting that the optimum system configuration would be country specific. Despite being marginally more costly in small trees at short corridor lengths (75 m), the single fully-integrated machine was considered the working configuration of choice under Norwegian conditions.


      PubDate: 2015-06-26T19:18:25Z
       
  • Editorial Board
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135




      PubDate: 2015-06-26T19:18:25Z
       
 
 
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