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  Subjects -> AGRICULTURE (Total: 719 journals)
    - AGRICULTURAL ECONOMICS (72 journals)
    - AGRICULTURE (490 journals)
    - CROP PRODUCTION AND SOIL (91 journals)
    - DAIRYING AND DAIRY PRODUCTS (26 journals)
    - POULTRY AND LIVESTOCK (40 journals)

AGRICULTURE (490 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   (Followers: 1)
Acta Technologica Agriculturae     Open Access   (Followers: 3)
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: 20)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 10)
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: 9)
African Journal of Horticultural Science     Open Access   (Followers: 2)
African Journal of Range & Forage Science     Hybrid Journal   (Followers: 5)
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: 79)
Agricultural History Review     Full-text available via subscription   (Followers: 1)
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: 6)
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: 34)
Agriprobe     Full-text available via subscription  
Agriscientia     Open Access  
Agrivita : Journal of Agricultural Science     Open Access   (Followers: 4)
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: 15)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 23)
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: 6)
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  
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: 13)
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]
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • Editorial Board
    • Abstract: Publication date: March 2015
      Source:Biosystems Engineering, Volume 131




      PubDate: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • Validation of a computerised technique for automatically tracking and
           measuring the inferior vena cava in ultrasound imagery
    • Abstract: Publication date: Available online 7 March 2015
      Source:Biosystems Engineering
      Author(s): Spencer Bellows , Mohamed Shehata , Jordan Smith , Peter Mcguire , Andrew Smith
      Accurate resuscitation of the critically-ill patient using intravenous fluids and blood products is a challenging, time sensitive task. Ultrasound of the inferior vena cava (IVC) is a non-invasive technique currently used to guide fluid administration, though multiple factors such as variable image quality, time, and operator skill challenge mainstream acceptance. This study represents a first attempt to develop and validate an algorithm capable of automatically tracking and measuring the IVC, compared to human operators across a diverse range of image quality. Minimal tracking failures and high levels of agreement between manual and algorithm measurements were demonstrated on good quality videos. Addressing problems such as gaps in the vessel wall and intra-lumen speckle should result in improved performance in average and poor quality videos. Semi-automated measurement of the IVC for the purposes of non-invasive estimation of circulating blood volume poses challenges, but it is feasible.


      PubDate: 2015-05-26T08:11:55Z
       
  • Statistical modelling of ammonia absorption in an acid spray scrubber
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Lara Jane S. Hadlocon , Alfred B.O. Soboyejo , Lingying Zhao , Heping Zhu
      The use of acid spray wet scrubbers for recovering ammonia (NH3) emissions is promising due to its high NH3 removal efficiency, simplicity in design, and minimal pressure drop contribution on fans. An experimental study was conducted to evaluate the performance of a lab-optimised acid spray scrubber using simple modelling tools. Important parameters that significantly affect scrubber efficiency were identified as inlet NH3 concentration, air retention time, Sauter mean diameter of spray droplets, and liquid flow rate. Two statistical models (additive and multiplicative models) were developed from the experimental data using regression analysis of scrubber efficiency as a function of the significant operating parameters. The additive model had better performance accuracy with an R2 value of 0.93, MSE of 0, RMSE of 0.06, and MAPE of 8.89%. Both models have good predictive ability based on residual analysis, power analysis, and cross-evaluation. This study was able to develop simplified models to aid in predicting NH3 removal efficiency of an acid spray scrubber, which can be installed at animal facilities for NH3 abatement.


      PubDate: 2015-05-26T08:11:55Z
       
  • Numerical investigation of plant tissue porosity and its influence on
           cellular level shrinkage during drying
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): H.C.P. Karunasena , Y.T. Gu , R.J. Brown , W. Senadeera
      Dried plant food products are increasing in demand in the consumer market, leading to continuing research to develop better products and processing techniques. Plant materials are porous structures, which undergo large deformations during drying. For any given food material, porosity and other cellular parameters have a direct influence on the level of shrinkage and deformation characteristics during drying, which involve complex mechanisms. In order to better understand such mechanisms and their interrelationships, numerical modelling can be used as a tool. In contrast to conventional grid-based modelling techniques, it is considered that meshfree methods may have a higher potential for modelling large deformations of multiphase problem domains. This work uses a meshfree based microscale plant tissue drying model, which was recently developed by the authors. Here, the effects of porosity have been newly accounted for in the model with the objective of studying porosity development during drying and its influence on shrinkage at the cellular level. For simplicity, only open pores are modelled and in order to investigate the influence of different cellular parameters, both apple and grape tissues were used in the study. The simulation results indicated that the porosity negatively influences shrinkage during drying and the porosity decreases as the moisture content reduces (when open pores are considered). Also, there is a clear difference in the deformations of cells, tissues and pores, which is mainly influenced by the cell wall contraction effects during drying.


      PubDate: 2015-05-26T08:11:55Z
       
  • Photocatalytic degradation of ethylene on mesoporous TiO2/SiO2
           nanocomposites: Effects on the ripening of mature green tomatoes
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): M.L.V. de Chiara , S. Pal , A. Licciulli , M.L. Amodio , G. Colelli
      Ethylene (C2H4) acts as plant hormone in horticultural and ornamental crops, and is responsible for a variety of effects that could be beneficial or detrimental. It accelerates senescence, stimulates chlorophyll loss, enhances excessive softening, promotes degreening and browning of vegetal tissues. These reported effects should be avoided during postharvest handling. In this study the photocatalytic degradation of C2H4 using mixed titania/silica (TiO2/SiO2) materials under UV light irradiation was investigated. Mixed phase TiO2/SiO2 nanocomposites with varying TiO2/SiO2 weight ratios were prepared by sol–gel method under mild hydrothermal conditions. Five types of nanocomposite powders, with weight percentage of TiO2:SiO2 of 100:0, 90:10, 80:20, 70:30, and 0:100 were prepared and are named as TiO2, 90Ti–10Si, 80Ti–20Si, 70Ti–30Si, and SiO2, respectively. The photocatalytic degradation test in the gas phase was conducted in a glass chamber using UV light as the irradiation source. The degradation efficiency of the different catalysts was investigated by measuring the percentage reduction of C2H4 in the reaction chamber at given time interval. It was observed that 80Ti–20Si sample showed the best degradation activity, resulting in complete ethylene removal from the atmosphere. The reduction rate increased when the contact time with the photocatalyst was prolonged. Mature green tomatoes were exposed to an ethylene-enriched atmosphere treated with 80Ti–20Si nanocomposite. The effect of photocatalytic ethylene removal was evident in the slower epicarp colour evolution compared to control samples. The developed material could be suitable for postharvest handling of the fresh produce (e.g. tomatoes) to prolong their shelf life and reduce losses.
      Graphical abstract image

      PubDate: 2015-05-26T08:11:55Z
       
  • Comparing the hydrolysis and biogas production performance of alkali and
           acid pretreatments of rice straw using two-stage anaerobic fermentation
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Dianlong Wang , Ping Ai , Liang Yu , Zhongxin Tan , Yanlin Zhang
      To enhance rice straw degradation and improve biogas production in a two-stage anaerobic system, rice straw was treated with either dilute alkali or acid. Firstly, the effects of NaOH or HCl concentration, temperature and time on glucose conversion, degradation of cellulose and hemi-cellulose were investigated. It was found that glucose conversion rate and the organic matter content were greater with alkali rather than acid pretreatment. Suitable conditions for hydrolysis using NaOH pretreatment were 2% (w/w), 60 h and 60 °C. With these conditions the glucose conversion rate was 55.5%. Secondly, the hydrolysate was used as substrate for batch anaerobic fermentation tests at different organic loadings. The maximum methane yield of hydrolysate from NaOH pretreatment was 193.2 ml g−1 [COD]. For the HCl pretreatment, the maximum methane production rate was 287.0 ml g−1 [COD] which was 43.89% higher than with NaOH. Although the NaOH solution was more efficient in improving rice straw hydrolysis, the hydrolysate from the HCl pretreatment had greater methane production at a similar organic loading.


      PubDate: 2015-05-26T08:11:55Z
       
  • Arrhenius activation energy for water diffusion during drying of tomato
           leathers: The concept of characteristic product temperature
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Cecilia Fiorentini , Silvana M. Demarchi , Natalia A. Quintero Ruiz , R. Martín Torrez Irigoyen , Sergio A. Giner
      The drying kinetics of tomato leathers was studied between 40 and 80 °C and the corresponding thermal histories were recorded. As air and product temperatures were found to be considerably different during the drying runs, the original concept of “characteristic product temperature” was proposed. It is defined as the temperature corresponding to the time at which the instantaneous drying rate is equal to the mean drying rate. Then, the Arrhenius activation energies (E a ) obtained by two methods were compared: (1) correlating the diffusion coefficient (D) with the air temperature and (2) correlating D with the characteristic product temperature. Drying curves comprised a “wet zone”, where moisture content fell almost linearly with time, and a subsequent “dry zone”. In the first zone, the Arrhenius relationship with the air temperature yielded an E a of 18.6 kJ mol−1 whereas, when utilising the characteristic product temperature the activation energy was 47.3 kJ mol−1, comparable to the enthalpy of water desorption. In the second zone, activation energies were 21.7 and 26.6 kJ mol−1, respectively. Molecular mobility theory suggests a stronger temperature dependence of diffusion-limited phenomena in high moisture content matrices and thus would forecast a higher E a for the wet zone. Therefore, the characteristic product temperature is more meaningful than the air temperature in the Arrhenius relationship.


      PubDate: 2015-05-26T08:11:55Z
       
  • Feasibility study on Huanglongbing (citrus greening) detection based on
           WorldView-2 satellite imagery
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Xiuhua Li , Won Suk Lee , Minzan Li , Reza Ehsani , Ashish R. Mishra , Chenghai Yang , Robert L. Mangan
      Huanglongbing (HLB) is a devastating citrus disease worldwide, without known cure. Since this disease shows visible symptoms on newly developed canopies, remote sensing methods based on spectral principles are considered as an effective tool. To explore a fast way to monitor HLB in large citrus groves, a satellite multispectral (MS) image with a 2-m resolution acquired by WorldView-2 was studied to evaluate its capability on HLB detection. Ground truth was conducted and two spectral libraries were constructed. Library 1 was based on RTK GPS locations, and Library 2 was combined with prior knowledge from the ground spectral features. To compare with the classification accuracy of previous work using airborne spectral images, the same classification methods were carried out. In the satellite MS image, Library 2 had higher average overall accuracy, higher Kappa coefficient, and higher producer's and user's accuracies than Library 1, indicating Library 2 which combined with prior knowledge was more effective. Mahalanobis distance had the highest overall accuracy of 81% and a Kappa coefficient of 0.464 with Library 2. The accuracy comparison between the satellite MS image and the airborne spectral images showed that the satellite MS image had the highest average producer's accuracy with Library 2, followed by the airborne MS image and the satellite MS image with Library 1, indicating that construction of an effective library was the most important step, and that the satellite MS image with a proper spatial resolution showed good potential to be a better choice than the airborne spectral image.


      PubDate: 2015-05-26T08:11:55Z
       
  • Multi-temporal imaging using an unmanned aerial vehicle for monitoring a
           sunflower crop
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Francisco Agüera Vega , Fernando Carvajal Ramírez , Mónica Pérez Saiz , Francisco Orgaz Rosúa
      The objective of this study is to determine the capability of an unmanned aerial vehicle system carrying a multispectral sensor to acquire multitemporal images during the growing season of a sunflower crop. Measurements were made at different times of the day and with different resolutions to estimate the normalised difference vegetation index (NDVI) and study its relationship with several indices related to crop status with the aim of generating useful information for application to precision agriculture techniques. NDVI was calculated from images acquired on four different dates during the cropping season. On two of these dates, two images were acquired to determine how the time of day when the images were taken influences NDVI value. To study the influence of image resolution on NDVI, the original images were resampled to 30 × 30 and 100 × 100 cm pixel sizes. The results showed that the linear regressions between NDVI and grain yield, aerial biomass and nitrogen content in the biomass were significant at the 99% confidence level, except during very early growth stages, whereas the time of day when the images were acquired, the classification process, and image resolution had no effect on the results. The methodology provides information that is related to crop yield from the very early stages of growth and its spatial variability within the crop field to be harvested, which can subsequently be used to prescribe the most appropriate management strategy on a site-specific basis.


      PubDate: 2015-05-26T08:11:55Z
       
  • Modelling soil water dynamics of full and deficit drip irrigated maize
           cultivated under a rain shelter
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): María G. González , Tiago B. Ramos , Reimar Carlesso , Paula Paredes , Mirta T. Petry , Juliano D. Martins , Núbia P. Aires , Luis S. Pereira
      The model HYDRUS-1D was used to simulate soil water dynamics of full and deficit irrigated maize grown under a rainout shelter during two crop seasons. Four irrigation treatments were established based on the amount of water applied to fulfil crop water requirements. Treatment D1 was irrigated to fully satisfy crop water requirements, while treatments D2 (mild deficit), D3 (moderate deficit), and D4 (severe deficit) were for increased controlled water stress conditions. The computation and partitioning of evapotranspiration data into soil evaporation and crop transpiration was carried out with the SIMDualKc model, and then used with HYDRUS-1D. The soil hydraulic properties were determined from numerical inversion of field water content data. The compensated root water uptake mechanism was used to describe water removal by plants. The HYDRUS-1D model successfully simulated the temporal variability of soil water dynamics in treatments irrigated with full and deficit irrigation, producing RMSE values that varied between 0.014 and 0.025 cm3 cm−3 when comparing model simulations with field measurements. Actual transpiration varied between 224 and 483 mm. Potential transpiration reductions varied from 0.4 to 48.8% due to water stress, but plants were able to compensate for the water deficits in the surface layers by removing more water from the deeper, less stressed layers. HYDRUS-1D water balance estimates were also comparable with the corresponding ones determined with the SIMDualKc water balance model. Both modelling approaches should contribute to improve the web-based IRRIGA system, used to support farm irrigation scheduling in Brazil.


      PubDate: 2015-05-26T08:11:55Z
       
  • Editorial Board
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132




      PubDate: 2015-05-26T08:11:55Z
       
  • Continuous in-house acidification affecting animal slurry composition
    • Abstract: Publication date: April 2015
      Source:Biosystems Engineering, Volume 132
      Author(s): Maibritt Hjorth , Giorgia Cocolo , Kristoffer Jonassen , Lone Abildgaard , Sven G. Sommer
      The emerging slurry acidification technology affects gaseous emissions, fertiliser value, biogas production and solid–liquid separation; however, maximising the advantages is difficult, as the effect of acidification on the slurry characteristics resulting in those observations remains unclarified. A full-scale study was therefore performed, comparing pig slurry from normal in-house slurry management with pig slurry from housing with daily in-house acidification to pH 5.5. The effect on organic, inorganic and particles was evaluated. Increasing dissolved P, Mg and Ca contents indicated mineral dissolution in acidified slurry. Acceleration of carbohydrate hydrolysis was indicated, while deceleration of microbial acidogenesis, acetogenesis, methanogenesis and sulphate reduction was indicated. The particles were larger following acidification treatment causing a lower viscosity, likely due to acidification-induced aggregation. Overall, the acidified slurry was significantly different from untreated slurry; it had higher conductivity, more dissolved inorganic components, fewer small organic compounds, more large dissolved organic compounds, and larger particles.


      PubDate: 2015-05-26T08:11:55Z
       
  • Design of a real-time emergency telemedicine system for remote medical
           diagnosis
    • Abstract: Publication date: Available online 23 April 2015
      Source:Biosystems Engineering
      Author(s): Nuria N. Castellano , Jose A. Gazquez , Rosa M. García Salvador , Antonio Gracia-Escudero , Manuel Fernandez-Ros , Francisco Manzano-Agugliaro
      In routine clinical practice of emergency care, it is very difficult to perform diagnostic procedures during ambulance transport. This can lead to a delay in the patient's diagnosis and, consequently, in the patient's treatment until arrival at the hospital. Although this situation does not imply notable risk in the majority of pathologies, in anticoagulated patients, this delay can be fatal. In this study, a system is discussed that would minimise the response time before the medical administration of anti-haemorrhagic or antithrombotic treatments that would mitigate or even eliminate the dramatic consequences of the progression of intracranial haemorrhage. The aim of this study is to design a real-time emergency telemedicine system for remote medical diagnosis and to demonstrate that it is possible to perform haematological tests in an ambulance in terms of an international normalised ratio (INR) using wireless transmission, accurately and in real-time, to the referral hospital. The main and novel component of our system is a hybrid network that enables secure long-distance communication from an ambulance. The results of the tests in the ambulance are such that there were no significant differences between the values obtained from the samples analysed during travel in the ambulance and those analysed in the laboratory. Transmitting this information immediately to the hospital may involve administering early treatment during the transfer as prescribed by the medical staff that have access to both the data and to the patient's clinical history. In conclusion, the telemedicine system designed for real-time emergencies opens new perspectives for remote medical diagnosis.
      Graphical abstract image

      PubDate: 2015-05-26T08:11:55Z
       
  • A web-based framework for anatomical assessment of the retina using OCT
    • Abstract: Publication date: Available online 23 April 2015
      Source:Biosystems Engineering
      Author(s): Ana González-López , Marcos Ortega , Manuel G. Penedo , Pablo Charlón
      Optical Coherence Tomography (OCT) is a clinical standard imaging technique in ophthalmology, which provides much more information than other classical modalities. Since retinal morphology and pathological structures can be identified in an effective way in the OCT images, image processing-based methods are emerging to extract their information. As a prior step to any automatic application for feature extraction, delimitation of retinal layers must be automated. On the other hand, medical research needs to process a large amount of information from different patients and the clinical studies are usually performed in a multi-centre schema. Therefore, not only is automation of retinal layer segmentation needed, but also a flexible framework must be designed to allow the experts to manage all clinical data, as well as extracting features of interest. With that aim, this work presents a framework for OCT image processing, which provides automatic procedures for retinal layer segmentation and the extraction of different statistics for medical-support. A web-based interface was designed in order to make it available to the ophthalmic experts and accessible from different centres. Since the framework was used by ophthalmologists in a real case scenario, its robustness and suitability for this task are shown, making it a very relevant tool for clinical and research purposes.


      PubDate: 2015-05-26T08:11:55Z
       
  • Influence of biodeposition treatment on concrete durability in a sulphate
           environment
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Farzaneh Nosouhian , Davood Mostofinejad , Hasti Hasheminejad
      Bacterial carbonate precipitation, which is based on urea hydrolysis, has been used as a surface treatment technique to decrease the permeation properties of concrete. Since permeability acts as the main reason of concrete degradation in harsh environments, this study evaluates microbial surface treatment in order to prevent sulphate ions penetration. Five groups of concrete specimens were cast and cured and were then surface treated applying three different microbial suspensions employing Sporosarcina pasteurii, Bacillus subtilis and Bacillus sphaericus bacteria. Durability was assessed through the mass losses, volume changes (expansion), water absorption and compressive strength. In order to consider further permeation properties, chloride penetration of biologically treated concrete was examined by a rapid chloride permeability test (RCPT). Experimental results and a durability loss index (DLI) indicated that biological surface treatment reduces concrete degradation in sulphate environments and improves durability characteristics. Also, the RCPT results confirmed that this technique limits chloride penetration into the concrete.


      PubDate: 2015-05-26T08:11:55Z
       
  • A new colour vision system to quantify automatically foliar discolouration
           caused by insect pests feeding on leaf cells
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): A. Clément , T. Verfaille , C. Lormel , B. Jaloux
      Leaf colour and leaf area are key parameters for many plant studies, including plant protection. The quantification of foliar bleached area is often used to evaluate the strength of plant attack by pests or diseases, to compare the efficiency of different treatments, the resistance of some populations, and to set up some control methods. The quantification of such area by human vision often lacks accuracy and reliability. Image analysis systems could bring a more accurate and objective measure, and could be automated to treat a great number of samples. Such an automated tool has been developed in order to measure quantitatively foliar bleaching due to the sycamore lace bug, Corythucha ciliata (SAY) on Plane tree. This tool was built up with a colour image capture bench and a fast automated segmentation process based on an original chlorophyll histogram unsupervised classification. Dedicated software was developed and integrated in an operational image processing platform capable of routine use by non-specialists in image analysis. The accuracy of the tool was determined by comparison to human expert segmentation. A very low error rate was observed in the absence of artefacts, but artefacts such as powdery mildew symptoms were not well distinguished and lead to weaker performance. Comparing its reliability and robustness to classical visual estimation and classification method, the tool performance was similar to the most experienced rater. The advantage of such a system is the possibility to treat automatically a large number of pictures and produce accurate, reliable, repeatable and non-subjective quantitative measurements.


      PubDate: 2015-05-26T08:11:55Z
       
  • Development of head loss equations for self-cleaning screen filters in
           drip irrigation systems using dimensional analysis
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Quanli Zong , Tiegang Zheng , Huanfang Liu , Cuijin Li
      Two equations for computing head loss in self-cleaning screen filter when using tap water and sand water mixture were developed using dimensional analysis. The parameters influencing head losses were considered to be eleven parameters representing the filter properties; filtration level, total filtration surface, flow rate, concentration of total sand, filtration time, inside diameter of the inlet and outlet pipes, mean filtration velocity, mean diameter of sand particle size distribution, water viscosity and water density. These variables were incorporated into eight dimensionless groups obtained through Buckingham's method. Two experiments to analyse head losses were carried out using 178 μm and 124 μm screen filters. A total of 54 runs for tap water and 58 filtration cycles for sand water mixture were carried out to obtain 54 and 2152 experimental points respectively, enabling the developed equations to be correlated. The developed equations were satisfactorily adjusted using the experimental data. Despite the adjustments of the equations being significant, regression coefficients were not always high. A comparison between the predicted and the measured head losses with three screen filters was in close agreement with a correlation coefficient of 0.902 for tap water and 0.832 for sand water mixture, respectively. The performance of equation was also compared with equations developed from the literature. The equations from Puig-Bargués et al. (2005b) Biosystems Engineering, 92 (3), p383–390 and this study provided good predictions, compared to other equations available in the literature.


      PubDate: 2015-05-26T08:11:55Z
       
  • Decision making models embedded into a web-based tool for assessing pest
           infestation risk
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133
      Author(s): Isabel M. del Águila , Joaquín Cañadas , Samuel Túnez
      Current practices in agricultural management involve the application of rules and techniques to ensure high quality and environmentally friendly production. Based on their experience, agricultural technicians and farmers make critical decisions affecting crop growth while considering several interwoven agricultural, technological, environmental, legal and economic factors. In this context, decision support systems and the knowledge models that support them, enable the incorporation of valuable experience into software systems providing support to agricultural technicians to make rapid and effective decisions for efficient crop growth. Pest control is an important issue in agricultural management due to crop yield reductions caused by pests and it involves expert knowledge. This paper presents a formalisation of the pest control problem and the workflow followed by agricultural technicians and farmers in integrated pest management, the crop production strategy that combines different practices for growing healthy crops whilst minimising pesticide use. A generic decision schema for estimating infestation risk of a given pest on a given crop is defined and it acts as a metamodel for the maintenance and extension of the knowledge embedded in a pest management decision support system which is also presented. This software tool has been implemented by integrating a rule-based tool into web-based architecture. Evaluation from validity and usability perspectives concluded that both agricultural technicians and farmers considered it a useful tool in pest control, particularly for training new technicians and inexperienced farmers.
      Graphical abstract image

      PubDate: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • Editorial Board
    • Abstract: Publication date: May 2015
      Source:Biosystems Engineering, Volume 133




      PubDate: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • Editorial Board
    • Abstract: Publication date: June 2015
      Source:Biosystems Engineering, Volume 134




      PubDate: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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: 2015-05-26T08:11:55Z
       
  • 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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