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  Subjects -> AGRICULTURE (Total: 724 journals)
    - AGRICULTURAL ECONOMICS (71 journals)
    - AGRICULTURE (496 journals)
    - CROP PRODUCTION AND SOIL (91 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: 1)
Acta agriculturae Slovenica     Open Access   (Followers: 5)
Acta Agrobotanica     Open Access   (Followers: 3)
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: 11)
Advances in Life Science and Technology     Open Access   (Followers: 6)
AFBM Journal     Open Access  
Africa Development     Open Access   (Followers: 19)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 9)
African Journal of Agricultural Research     Open Access   (Followers: 3)
African Journal of Food Science     Open Access   (Followers: 5)
African Journal of Food, Agriculture, Nutrition and Development     Open Access   (Followers: 10)
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: 48)
Agricultural History     Full-text available via subscription   (Followers: 69)
Agricultural History Review     Full-text available via subscription   (Followers: 2)
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: 35)
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: 2)
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: 10)
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: 1)
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: 22)
Applied Financial Economics Letters     Hybrid Journal   (Followers: 7)
Arboricultural Journal : The International Journal of Urban Forestry     Hybrid Journal   (Followers: 6)
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)
Berkala Ilmiah Pertanian     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)

        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  [2812 journals]
  • 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
       
  • Modelling of fraction of absorbed photosynthetically active radiation in
           vegetation canopy and its validation
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Rongyuan Liu , Huazhong Ren , Suhong Liu , Qiang Liu , Xiaowen Li
      The Fraction of Absorbed Photosynthetically Active Radiation (FPAR) has been identified as one of the key parameters in calculating ecosystem productivity. The objective of this paper is to model the vertical profile of FPAR in the canopy using a radiative transfer model, the Modified Simultaneous Heat and Water (MSHAW) radiation model. Model analysis indicated that the vertical distribution of the canopy FPAR was dependent on the leaf area index (LAI), average leaf orientation angle (ALA), solar position, and sky conditions. In the validation of the MSHAW model with three varieties of wheat leaf profile at different growth stages, two parabolic functions were developed to approximately reconstruct the shape of the wheat leaf for the first time and, consequently, the vertical profiles of LAI and ALA used to drive the MSHAW model were estimated. The validation results indicated that the estimated FPAR was close to the measurements made with the SunScan canopy analysis system with an RMSE of approximately 0.15 for the continuous canopy. Finally, this paper also discusses a promising method to perform time normalisation on canopy FPAR data using multiple temporal remotely sensed data observations and to retrieve FPAR from remotely sensed data based on the analysis of the MSHAW model.


      PubDate: 2015-06-26T19:18:25Z
       
  • Effect of bioethanol conversion efficiency and ratio of rice paddy area to
           flatland on energy consumption and CO2 emission of rice straw transport
           process in Japan
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Takahiro Orikiasa , Poritosh Roy , Ken Tokuyasu , Nobutaka Nakamura , Shoji Koide , Takeo Shiina
      In Japan, rice straw is recognised as the most promising biomass for bioethanol production based on the amount and availability. This study examined the energy consumption and the CO2 emissions of the rice straw transport process. Specifically, we investigated the effects of the ethanol conversion efficiency (ε) and the ratio of the rice paddy area to flatland (γ) on the CO2 emission and energy consumption of the rice straw transport process. The energy consumption and the CO2 emissions (ε: 0.60–1.0; γ: 0.050–0.20) were determined to be 0.17–0.37 MJ L−1 and 0.012–0.025 kg L−1, respectively. The predicting model for the energy consumption and the CO2 emissions of the rice straw transport process was constructed, and the energy consumption and the CO2 emissions were proportional to the ethanol conversion efficiency raised to the −1.5 power and γ raised to the −0.5 power. These results showed that the lower γ, the higher the energy consumption of the rice straw transport process. Furthermore, the energy consumption of the rice straw transport process increased at large-scale plants because of the higher value of average transportation distance.


      PubDate: 2015-06-26T19:18:25Z
       
  • Methane production potential from Miscanthus sp.: Effect of harvesting
           time, genotypes and plant fractions
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Radziah Wahid , Susanne Frydendal Nielsen , Veronica Moset Hernandez , Alastair James Ward , Rene Gislum , Uffe Jørgensen , Henrik Bjarne Møller
      The perennial C4 grass miscanthus was evaluated for use as an energy crop for methane production when harvested green in the autumn. Miscanthus × giganteus (M. × giganteus) and Miscanthus sinensis (M. sinensis) were harvested on five occasions, from August to November 2012. Methane yields from stems and leaves were analysed using batch assay after 90 d digestion. Estimated dry matter yields were highest on 1st October for M. × giganteus and 13th September for M. sinensis. Cellulose and lignin contents were greater with M. × giganteus than M. sinensis and low lignin content in leaves led to rapid degradation during the early periods of anaerobic batch assay. After 90 d of anaerobic digestion, cumulative specific methane yields for M. × giganteus varied for stem and leaf from 285 to 333 and 286 to 314 Nl (normalised litre) kg−1 [VS] and 291 to 312 and 298 to 320 Nl kg−1 [VS] for M. sinensis. Estimated methane yields per ha were positively correlated with the dry matter yields of miscanthus (r = 0.92) and the optimal harvesting time was between September–October. Methane yield at optimal harvest time was estimated as 3.824 × 106 Nl ha−1 (stem) and 1.605 × 106 Nl ha−1 (leaf) for M. × giganteus and 3.507 × 106 Nl ha−1 (stem) and 2.957 × 106 Nl ha−1 (leaf) for M. sinensis. There was a discrepancy between the estimating dry matter yield by sampling single shoots and whole plot harvesting. This needs to be further investigated.


      PubDate: 2015-06-26T19:18:25Z
       
  • Effect of blade oblique angle and cutting speed on cutting energy for
           energycane stems
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Sunil K. Mathanker , Tony E. Grift , Alan C. Hansen
      Energycane is a promising bioenergy crop for warm south-eastern US regions and existing sugarcane machinery is being adapted for energycane cultivation. Because of energycane's comparatively higher fibre content and smaller stem diameters, the cutting blades must be optimized for energycane harvesting and size reduction. To optimize cutting blade designs, this study investigated the effect of cutting speed and blade oblique angle on cutting energy. An impact type cutting mechanism was used to determine the cutting energy cost of individual stems. The results showed that the specific cutting energy increases with cutting speed. The lowest average specific energy was 0.26 J mm−1 for a 60° oblique cut at an average cutting speed of 7.9 m s−1, whereas the highest average specific cutting energy was 1.24 J mm−1 for a straight cut at an average cutting speed of 16.4 m s−1. The specific cutting energy showed a close correlation with stem diameter and stem cross-sectional area. For a 30° oblique angle at 11.3 m s−1 average cutting speed, the cutting energy varied from 4.5 to 15 J as the energycane stem diameter varied from 11 to 17 mm. Comparisons with sugarcane studies indicated that optimisation of cutting speed and blade oblique angle can result in significant savings in cutting energy, whilst simultaneously improving the quality of cut. This study emphasises the need for further investigation of the energycane cutting process especially at higher cutting speeds with cutting devices with varying moments of inertia.
      Graphical abstract image

      PubDate: 2015-06-26T19:18:25Z
       
  • A Mastercurve to predict annual ryegrass (Lolium rigidum) seed
           devitalisation when exposed to multiple single sided impacts
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Nicholas K. Berry , John M. Fielke , Chris Saunders
      A strategy to control herbicide resistant weeds is to use an impact mill to devitalise weed seeds as they exit a combine harvester. To model the impact milling of weed seeds, the milling response was split into material and machine functions separating the effect of seed properties from mill design and operational parameters. The material function was determined by subjecting annual ryegrass seeds (Lolium rigidum) to multiple single sided impacts using a rotational impact tester. The number of impacts, impact speed and seed moisture content were varied. Seed devitalisation was measured by germinating seeds in soil bins in a controlled environment room. Seed devitalisation increased with the number of impacts, the impact speed and decreasing moisture content. Seed devitalisation did not depend on the order of an impact sequence when exposed to multiple impacts at three different speeds. A threshold minimum energy per impact of 0.3991 kJ kg−1 (equivalent to ∼ 28 m s−1) was observed, below which almost zero devitalisation occurred. A material function Mastercurve for devitalisation was developed using this threshold energy level and one other material parameter which described a seed's resistance to fracture. The Mastercurve was able to accurately predict (r 2 = 0.94) devitalisation of annual ryegrass seeds (11.3% m.c.) by the number of impacts above the threshold speed and impact speed in any impact sequence. The Mastercurve presented will be able to be used in future studies with a machine function to design impact mills to mechanically devitalise annual ryegrass seeds.


      PubDate: 2015-06-26T19:18:25Z
       
  • The automatic detection of dairy cow feeding and standing behaviours in
           free-stall barns by a computer vision-based system
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Simona M.C. Porto , Claudia Arcidiacono , Umberto Anguzza , Giovanni Cascone
      Changes in cow behaviour may occur in relation to health disorders. In literature the suitability of using behavioural changes to provide an early indication of disease is studied. The possibility of achieving a real-time analysis of a number of specific changes in behaviours, such as lying, feeding, and standing, is crucial for disease prevention. Cow feeding and standing behaviour detectors were modelled and validated by defining a methodology based on the Viola–Jones algorithm and using a multi-camera video-recording system to obtain panoramic top-view images of an area of the barn. Assessment of the detection results was carried out by comparison with the results generated by visual recognition. The ability of the system to detect cow behaviours was shown by the high values of its sensitivity achieved for the behaviours of feeding and standing which were about 87% and 86%, respectively. Branching factor values for the two behaviours showed that one false positive was detected for every 13 and 6 well-detected cows, respectively. On the basis of these research outcomes, the proposed system is suitable for computing cow behavioural indices and the real-time detection of behavioural changes.


      PubDate: 2015-06-26T19:18:25Z
       
  • Estimation of Weibull function parameters for modelling tree diameter
           distribution using least squares and artificial neural networks methods
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Maria J. Diamantopoulou , Ramazan Özçelik , Felipe Crecente-Campo , Ünal Eler
      For reliable forest management planning, knowledge of stand diameter distributions is valuable, since it allows, for example, calculation of merchantable volume when combined with a taper equation. Due to its flexibility, and its ability to describe a wide range of uni-modal distributions, the two-parameter Weibull function has been reported as being one of the most simple and accurate functions for modelling tree diameter distributions. However, the complex nonlinear nature of the tree-diameter distributions leads to laborious simulation of the probability density function in the Weibull distribution. Because of this weakness, an investigation was conducted using standard least squares and Levenberg–Marquardt artificial neural network method. These methods were used as inner procedures for the accurate estimation of the scale and shape parameters required in Weibull distribution modelling, using a) a method of moments and b) a maximum likelihood estimation. Data from Crimean Juniper stands grown in the Mediterranean region of Turkey was used. From the computational results it was concluded that the method which gives the most reliable estimates is the maximum likelihood estimation procedure with recovery of the Weibull distribution parmeters using the Levenberg–Marquardt artificial neural network modelling method.


      PubDate: 2015-06-26T19:18:25Z
       
  • Sensitivity of thermal imaging and infrared thermometry to detect water
           status changes in Euonymus japonica plants irrigated with saline reclaimed
           water
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): María J. Gómez-Bellot , Pedro A. Nortes , María J. Sánchez-Blanco , María F. Ortuño
      The potential of thermal imaging and infrared thermometry for monitoring the effects of salinity on Euonymus japonica (euonymus) plants was assessed using the following irrigation treatments: Control (electrical conductivity (EC) < 1.2 dS m−1) and reclaimed water, RW (EC ≈ 4 dS m−1). The experiment was conducted for more than eight months in a plastic greenhouse. The diurnal course of canopy temperature (T c ) and the difference between canopy and air temperature (T c −T a ) for both sunlit and shaded sides was influenced by high concentration of salts in the reclaimed water. The negative relationship between T c and stomatal conductance (g s ) and between T c −T a and g s in April was significant during most of the day, but specifically at midday. Regarding the effect of canopy side, better regression coefficients were obtained between T c and g s , and between T c −T a and g s on the sunlit side of the canopy than on the shaded side. However, except for the crop water stress index on the sunlit side of the canopy, few differences during the day were reported for thermal indices. From April onwards, canopy temperatures were higher in RW plants than in the control, indicating the dependence of canopy temperature on salinity. Comparing the sensitivity of discrete (stem water potential and g s ) and continuous (T c and thermal-derived parameters measured by infrared thermometers) indicators of saline stress, it was shown that T c and T c −T a were the most suitable plant-based indicators for precise irrigation scheduling.


      PubDate: 2015-06-26T19:18:25Z
       
  • Evaluation of four NIR spectrometers in the analysis of cattle slurry
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Giovanni Cabassi , Daniele Cavalli , Roberto Fuccella , Pietro Marino Gallina
      The composition of animal slurries is basic information required to arrange fertilisation plans that allow satisfactory crop yields and avoid environmental pollution. Slurry management based on measured composition data requires the development and adoption of analytical methods that are rapid, affordable and applicable directly in the field. NIR spectroscopy is a candidate technique for this application. In the present work, the performances of four NIR spectrometers, differing in optics, detectors and price, were investigated and compared: one FT-NIR and one dispersive benchtop instrument; a less expensive diode array dispersive instrument also suitable for online applications; and a low-cost interferometric portable instrument. Ninety-nine slurries, collected from livestock farms in Lombardy (Italy), were characterised using reference methods for dry matter (DM), ashes (ASH), total nitrogen (TKN), ammonium nitrogen (AN), organic nitrogen (ON), total carbon (TC) and total phosphorus (TP) content, and were used to investigate the performance of the four NIR spectrometers. The calibrations obtained from the two benchtop instruments for DM, ASH, TKN and TC were classified “useful” or “moderately useful”, while for AN and TP they were “useful for screening purposes”. The two portable instruments provided less accurate calibrations, with the exception of DM and TC which, in the case of the diode array instrument, performed similarly to the benchtop spectrometers. The higher resolution and, to a lesser degree, the wider spectral range of the two benchtop spectrometers contribute to explain their better calibration performances for TKN and AN.


      PubDate: 2015-06-26T19:18:25Z
       
  • Electro-osmotic dewatering of high moisture flax stems
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Gopu Raveendran Nair , Ashutosh Singh , Jiby Kurian , Vijaya Raghavan
      Retted flax stems contained high amounts of water from the pre-soaking and retting processes. Electro-osmotic dewatering was investigated as a pre-drying process for high-moisture flax stems using a bench electro-osmotic roller press. The various parameters affecting electroosmotic dewatering were cylinder pressure (1000 kPa–3000 kPa), applied voltage (12 V–36 V) and pre-soaking time of the flax stem (12 h–36 h). An experiment was designed using central composite design. From the experiments, a maximum of 38.34% of the total water contained in the stem was removed using 12 h soaking; 1000 kPa cylinder pressure and 36 V applied voltage during the electro-osmotic treatment. For a given soaking time, at 36 V with 3000 kPa cylinder pressure the maximum water removal occurred. The electro-osmotic permeability of the stems at various conditions was studied. In all the treatments, electro-osmotic permeability ranged between 3.32 × 10−5 m2 V−1 s−1 and 1.22 × 10−4 m2 V−1 s−1. Electro-osmotic permeability was found to increase with increasing water removal and decreased with increasing applied voltage.
      Graphical abstract image

      PubDate: 2015-06-26T19:18:25Z
       
  • Editorial Board
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133




      PubDate: 2015-06-26T19:18:25Z
       
  • Computational approach for tear film assessment based on break-up dynamics
    • Abstract: Publication date: Available online 16 May 2015
      Source:Biosystems Engineering
      Author(s): L. Ramos , N. Barreira , H. Pena-Verdeal , M.J. Giráldez , E. Yebra-Pimentel
      Dry eye syndrome is a common disorder of the tear film which affects a remarkable percentage of the population, impacting on quality of life. The study of the tear film stability is essential for the dry eye characterisation. The Break-Up Time (BUT) is a clinical test which computes the time the first tear film break-up appears. Besides the time, break-up properties can be related to specific aspects of the tear film that could affect dry eye severity. This work describes a fully automatic methodology to compute the BUT measurement and evaluate the dynamics of break-up areas. This methodology has been tested on a data set consisting of 18 tear film videos, achieving similar results to the manual annotations marked by the experts. This analysis provides useful additional information for the tear film assessment.


      PubDate: 2015-06-26T19:18:25Z
       
  • Effect of injection pressure and fluid volume and density on the jet
           dispersion pattern of needle-free injection devices
    • Abstract: Publication date: Available online 16 May 2015
      Source:Biosystems Engineering
      Author(s): Tyler M. Grant , Kevin D. Stockwell , Jason B. Morrison , Danny D. Mann
      Needle-free injection devices improve vaccinator safety and optimise vaccine delivery time by eliminating the use of needles involved with traditional vaccination techniques. Of significant importance is a full understanding of the relationships that exist between the injection properties and the depth and shape of the injectate's dispersion. Work has been done to characterise the distribution of human needle-free injection devices, but little research has been conducted on livestock injections, which operate at much higher pressures and volumes. Therefore, the aim of this research was to characterise the injection profile of a livestock needle-free injection device while varying the injection pressure and fluid volume and density. Water and porcine circovirus vaccine were injected into ballistic gelatin blocks and the injection mechanism was captured using high-speed photography. The volume was varied between 1.0 and 2.5 ml and orifice pressure between 40 and 220 MPa. It was found that pressure influenced the depth of penetration, but had little effect on the shape of the injection profile. In contrast, the volume and density increased the penetration depth and varied the dispersion pattern. These results can be used to better understand how the injection profile of a needle-free injection device changes given an initial set of parameters. This will be important for developing administration protocols that successfully deliver intradermal, subcutaneous, and intramuscular livestock injections.


      PubDate: 2015-06-26T19:18:25Z
       
  • Analysing the effect of particle size on the disintegration of distiller's
           spent grain compacts while drying in superheated steam medium
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Praveen Johnson , Jitendra Paliwal , Stefan Cenkowski
      Particle size distribution (PSD) in distiller's spent grain compacts was varied and their effect on the disintegration characteristics of compacts while drying in superheated steam (SS) was monitored. Volumetric change and stress-relaxation characteristics, in terms of hardness and asymptotic modulus (EA) for a 40% deformation, were analysed during the warm-up period (5  s) and after reaching the moisture levels of 40, 30 and 20% (w.b.) in SS. Results showed that particle size was inversely correlated with the expansion or the increase in volume of the compact during SS drying, and the hardness as well as the EA of the compact increased with a decrease in particle size of the compact. A stepwise regression method was used to determine appropriate variables for developing a multiple linear regression model for predicting the EA of the compact.


      PubDate: 2015-06-26T19:18:25Z
       
  • LED measurement for development of a non-destructive detector of
           unsuitable chicken eggs in influenza vaccine production
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Kohei Kimura , Kazuhiro Nakano , Shintaroh Ohashi , Kenichi Takizawa , Takayuki Nakano
      In Japan, fertilised chicken eggs are used to produce influenza vaccines; however, some eggs die and then contaminate the vaccine stock solution, which causes large economic losses and raises health concerns. Therefore, a non-destructive test that allows distinction of normal and unsuitable chicken eggs was developed, first using visible and near-infrared (VNIR) spectroscopy and subsequently a light-emitting diode (LED) light source. Eggs were sampled from an egg farm, and each of the eggs categorised as either normal or unsuitable using candling. Linear discriminant analysis was applied using wavelength absorbance data to distinguish between normal and unsuitable eggs. All of the optical absorbance values of the normal eggs were found to be higher than those of unsuitable eggs. To reduce the production cost, LED lights and photodiodes were used as the light source and light receptors, respectively. A discrimination rate of 92.9% was obtained when LED was used as the light source.


      PubDate: 2015-06-26T19:18:25Z
       
  • A decision tool for maize silage harvest operations
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Carlos Amiama , Noelia Cascudo , Luisa Carpente , Ana Cerdeira-Pena
      In forage harvesting, self-propelled harvesters (SPFHs) are the component that most affects the cost of the process because of their high operating costs. Therefore efficient management of the SFPH is essential. There are basically two ways to improve the SPFH performance: to reduce the travelling distance between fields and to design an efficient planning for the transport vehicles. A decision support tool has been developed for silage harvest operations to help farm managers, consultants, and technicians decide which resources they should use to minimise the cost of harvesting operations. The focus is on searching the routes that provide reduced travelling distances for the SPFH by prioritising the harvesting starting date for each farmer, and matching the SPFH and number of trucks to minimise the total cost of the maize silage harvesting cycle. The developed decision support system is compared to a real scenario in a maize harvesting season. Results show that by using the decision support tool, savings of over 15% can be obtained in distances travelled when compared with manual scheduling. Savings over 20% could be made if the restriction of using the starting harvesting dates requested by the farmers was relaxed. Under the conditions tested, if tolerance levels are not considered, the harvesting system is more sensitive to selecting correct transport management approach than to the efficient management of SPFH routes.


      PubDate: 2015-06-26T19:18:25Z
       
  • Development of stability indicators for dynamic Phase I overturn of
           conventional farm tractors with front axle pivot
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Zhen Li , Muneshi Mitsuoka , Eiji Inoue , Takashi Okayasu , Yasumaru Hirai
      Tractor overturns are serious potential hazards for operators. While rollover protective structures (ROPS) protect operators passively, greater protection can be achieved through theoretical prediction of a potential overturn. Given effective warning, an operator can act to correct a tractor's motion when a tyre is about to lose contact with the ground. Such a loss of contact is associated with the initiation of a Phase I tractor overturn. However, it remains unclear how the initiation of tractor overturn is influenced by certain factors. Furthermore, the current mathematical models for tractors should be further extended for general utilisation. This study was conducted to develop stability indicators based on a more general model for dynamic Phase I tractor overturn. We considered practical tractor configurations and motion characteristics in a three-dimensional (3D) reference frame in formulating the mathematical model. Tractor stability indicators for overturn and sideslip were derived from force calculations. A parametric study was conducted using an example tractor. The tractor speed and slope angle were found to affect the overturning stability significantly. The coefficient of maximum static friction was found to be the main factor contributing to tractor sideslip. Critical tractor speeds for various ground conditions were identified by considering the zero values of the tractor stability indicators. The critical tractor speed was determined as a function of the maximum static friction and the slope angle. By providing a display device based on ergonomics principles, the results of this study can be further implemented in the form of guidance to operators.


      PubDate: 2015-06-26T19:18:25Z
       
  • Effects of measurement technique and sample preparation on NIR
           spectroscopy analysis of livestock slurry and digestates
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): A. Finzi , R. Oberti , A.S. Negri , F. Perazzolo , G. Cocolo , F. Tambone , G. Cabassi , G. Provolo
      Near infrared spectroscopy (NIRS) was used to analyse livestock slurries and digestates. The purpose was to evaluate the influence of sample preparation, reading set-up and sample temperature during NIR scanning on digestates and livestock slurry samples. To obtain accurate and reproducible values of total solids (TS), total kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids (VFA) contained in dairy and pig slurry and digestate, a total of 36 samples were analysed from different farms in Lombardy, Italy. Three sample preparations (filtration, homogenisation and a raw control), two reading set-ups (petri dish and optical fibre) and three sample temperatures (10, 25 and 35 °C) were tested during NIR scanning. Results showed that analysis of livestock slurries and digestates by NIR spectrophotometry is influenced by sample preparation. Both filtered and homogenised samples generally showed higher correlations (r 2 ) and ratio of standard error of performance to standard deviation (RPD) (0.79 < r 2  > 0.98 and 2.26 < RPD > 6.99 for filtered samples; 0.30 < r 2  > 0.97 and 1.24 < RPD > 6.31 for homogenised samples) than raw samples (0.03 < r 2  > 0.95 and 1.05 < RPD > 4.73), but the better sample preparation was filtration. Spectral acquisition through petri dishes was slightly more accurate than through optical fibre. No observable effects on spectral analysis were caused by altering temperature in the range of 10–35 °C.


      PubDate: 2015-06-26T19:18:25Z
       
  • Feasibility of ambient loading of citrus fruit into refrigerated
           containers for cooling during marine transport
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Thijs Defraeye , Pieter Verboven , Umezuruike Linus Opara , Bart Nicolai , Paul Cronjé
      As an alternative to forced-air precooling, warm loading of citrus fruit into refrigerated containers for cooling during marine transport was explored. This practice could provide several logistic and economic savings. Although successful for resilient citrus fruits, the cooling process and performance of ambient loading have not been explored in a systematic manner. There is still a considerable potential to optimise the implementation of the technique and to apply it to more sensitive citrus or other fruits. Calculations identified the required cooling capacity of a refrigerated container as a function of the envisaged fruit cooling time, and these were complemented by a full-scale experiment. Although a refrigerated container was theoretically able to cool the produce in less than 5 days, the experiment showed that these cooling rates are not currently achieved in practice, bearing in mind that step-down cooling was applied. Future improvements in the technique point towards an improved box design and better stacking on the pallet, and to reducing airflow short-circuits between pallets.


      PubDate: 2015-06-26T19:18:25Z
       
  • Oil content determination scheme of postharvest oil palm for mobile
           devices
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Burawich Pamornnak , Somchai Limsiroratana , Mitchai Chongcheawchamnan
      In this paper, a simple scheme based on an image processing technique for determining oil content in postharvest oil palm (Elaeis guineensis Jacq.), implemented for a mobile device, is proposed. The scheme has three main algorithms for colour correction, classification and oil extraction rate (OER) determination. The colour correction algorithm can correct image colour from the device-dependence effect in the standard RGB (sRGB) colour model based on the determined device profile function. The classification process was developed on a two-layer feedforward neural network by using features from the hue value of oil palm fruits. The OER determination function was modelled by using a polynomial regression model based on the hue and saturation values. The results demonstrated that the proposed scheme can classify and determine the OER with a simple calculation. The scheme was implemented on a mobile device/phone and tested with 64 oil palm fruit samples. Compared with the standard Soxhlet extraction measurement, the scheme achieves a mean error of OER 2.20 with a postharvest OER range of 30–73%.


      PubDate: 2015-06-26T19:18:25Z
       
  • Experimental study of the ignition delay of diesel/biodiesel blends using
           a shock tube
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Vu Nguyen Hoang , Luong Dinh Thi
      Ignition delays of a pure biodiesel, which is produced from palm oil, as well as its blends with petroleum diesel were experimentally quantified using a preheated shock tube. The emission of OH∗ radical signals, which was observed by a photomultiplier via a monochromator, was used to identify the time for onset of ignition. Experiments were performed behind the reflected shock waves at a pressure of 0.12 MPa, equivalence ratios of 0.5, 1.0 and 1.5, and a range of temperatures from 1174 to 1685 K. Fuel blends B0, B20, B40, B60, B80 and B100 (corresponding to 0, 20, 40, 60, 80 and 100 vol% of biodiesel with petroleum diesel, respectively) were tested. The results show that ignition delay variations of blends versus temperature were similar to those of pure diesel fuel. It was consistently found that for all fuel blends, ignition delay increases with an increase in equivalence ratio. An equivalence ratio exponent of 0.73 in Arrhenius correlation was observed. At a constant equivalence ratio, the effect of biodiesel fraction on chemical ignition delay of the fuel blends was not significant. The overall activation energy of diesel/biodiesel mixtures in this study is 161,937.5 J mol−1.


      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
       
  • Editorial Board
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134




      PubDate: 2015-06-26T19:18:25Z
       
  • Mitigating emissions from pig and poultry housing facilities through
           air scrubbers and biofilters: State-of-the-art and perspectives
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Caroline Van der Heyden , Peter Demeyer , Eveline I.P. Volcke
      The global intensification of livestock production resulted in potentially higher emissions of ammonia, odour, particulate matter (PM) and greenhouse gases (nitrous oxide and methane). Air scrubbers and biofilters were introduced as a low ammonia emission housing technique. However, regulations with regard to the use of air scrubbers changed, including also removal efficiencies for odour and PM besides ammonia. In practice however, the required removal efficiencies for these pollutants are not always obtained, indicating the need of process optimisation in terms of process design and/or operation. When optimising air scrubbers, it is argued and recommended to anticipate the growing attention towards greenhouse gases, such as methane and nitrous oxide, which are present in exhaust air from animal housing facilities. However up till now, very little is known about the behaviour of greenhouse gases in air scrubbers and biofilters. Moreover, the formation of nitrous oxide in (biological) air scrubbing systems cannot be excluded. This contribution summarises the state-of-the-art of air scrubbers and biofilters for the reduction of emissions of ammonia, odour, nitrous oxide, methane and fine dust and points out perspectives for process optimisation in terms of design and control. The air and liquid flow configuration, packing dimensions and packing material should be carefully considered. Control options for water flow rate, water discharge and acid dosage need to be optimised. Dosage of apolar solvents and inoculation of the packing material can be innovative control options to achieve a better removal of less water-soluble components.


      PubDate: 2015-06-26T19:18:25Z
       
  • Model-based analysis of skill oriented labour management in a
           multi-operations and multi-worker static cut rose cultivation system
    • Abstract: Publication date: July 2015
      Source:Biosystems Engineering, Volume 135
      Author(s): Albertus van 't Ooster , Jan Bontsema , Eldert J. van Henten , Silke Hemming
      Worldwide competitive challenges urge growers to further improve operational performance. In this paper, the objective ‘model-based analysis and improvement of the operation of horticultural production systems’ was narrowed to ranking simulated labour management scenarios in a multi-operations and multi-worker static cut-rose cultivation system. Eight scenarios with worker skill as a central theme were simulated including a practical labour management scenario applied by a Dutch cut-rose grower. The GWorkS-model was prepared for simulation of disbudding and bending in addition to harvest, three crop operations representing over 90% of crop-bound labour time, as well as for full scale simulation of the greenhouse using all workers and equipment. The sub-models on disbudding and bending were verified using data acquired in practice. Both processes were reproduced accurately. The model study on work scenarios showed that labour organisation choices might yield up to 5 s per harvested rose difference in total labour time for harvest, bending and disbudding between the best and worst scenario, which is equivalent to 7.1 € m−2 labour costs difference per year. Scenarios pointed out that working with low skilled, low paid workers is not effective. Specialised workers were most time effective, −17.5% compared to the reference, but overall a permanent team of skilled generalists ranked best in a multi-factorial assessment. Reduced crop operation diversity per day improved labour organisational outputs but ranked almost the same as the reference. The reference scenario was outranked by 5 scenarios. Overall, the GWorkS-model provided clear answers to research questions using the full complexity of crop operations.


      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
       
  • VOC emissions from beef feedlot pen surfaces as affected by within-pen
           location, moisture and temperature
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134
      Author(s): Bryan L. Woodbury , John E. Gilley , David B. Parker , David B. Marx , Roger A. Eigenberg
      A laboratory study was conducted to evaluate the effects of pen location, moisture, and temperature on emissions of volatile organic compounds (VOC) from surface materials obtained from feedlot pens where beef cattle were fed a diet containing 30% wet distillers grain plus solubles. Surface materials were collected from the feed trough (bunk), drainage, and raised areas (mounds) within three feedlot pens. The surface materials were mixed with water to represent dry, wet, or saturated conditions and then incubated at temperatures of 5, 15, 25 and 35 °C. A wind tunnel and gas chromatograph-mass spectrometer were used to collect and quantify emissions of eight volatile fatty acids (VFAs), five aromatics and two sulfur-containing compounds. Pen location significantly (P < 0.05) affected measurements of 10 of the VOC with the largest values occurring for materials collected near the mound area. The largest VFA and aromatic emissions resulted for the dry moisture condition while wet and saturated conditions produced the largest sulfide emissions. Temperature affected emission of each VOC except indole, with values generally increasing as temperature increased. Odour activity value (OAV), which was the ratio of measured concentration of a single compound normalised to the odour threshold for that compound, was calculated for each compound. Four VFAs contributed 7.5% of the total OAV but only one aromatic, 4-methylphenol, was a major contributor to total OAV at 2.5%. In comparison, sulfide compounds contributed 87.3% of the total OAV. This research shows VOC emissions are affected by pen location, moisture condition, and temperature.


      PubDate: 2015-04-27T06:49:40Z
       
 
 
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