| 1. |
- Anerud, Erik, et al.
(författare)
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Evaluation of the performance of a three-dimensional vibrating test rig for cleaning stumps
- 2012
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Ingår i: Australian Journal of Agricultural Engineering. - 1836-943X. ; 3, s. 51-58
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Tidskriftsartikel (refereegranskat)abstract
- It has been shown that vibrating devices can successfully be used for separation and removal of unwanted/contaminant material, for both laboratory and full-scale industrial purposes. The presence of impurities on energy-rich softwood stumps is a major drawback when using stumps as fuel, since it leads to high ash content. Vibration methods can be an efficient approach to remove excess impurities and achieve acceptable ash content. Stumps are usually shaken in connection with harvesting and stored afterwards to facilitate the removal of contaminants. The required storage duration can lead to high dry matter losses and a faster and efficient cleaning method such as vibration is highly desirable. This study evaluated the performance of an adjustable three-dimensional vibrating test rig designed to assess the cleaning efficiency of vibration-based methods. Vibrating parameters such as acceleration amplitude, frequency and displacement of the test rig were determined for 12-24 mm distance between eccentric weight centre of mass and the rotating shaft of electric motors at rotation velocity 19.16-29.17 Hz. The acceleration amplitude ranged from 1.38 to 5.71 g. The parameters could be repeated irrespective of direction and number of vibration directions. The test rig was therefore considered to be a reliable tool for determining and evaluating the efficiency of vibration in removing contaminants from stumps.
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| 2. |
- Bulitta, Sorri Fufa, et al.
(författare)
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Modelling the Dynamic Response of Cattle Heart Rate During Loading for Transport
- 2011
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Ingår i: Australian Journal of Agricultural Engineering. - 1836-943X. ; 2, s. 66-73
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Tidskriftsartikel (refereegranskat)abstract
- Researchers in animal welfare and transport use heart rate (HR) as an important parameter to describe animal response to emotional and physical stresses. This study examined the dynamic HR response in cows to stress-inducing factors during loading for transport. The simulation model was developed using Powersim software via application of exponential function to describe the pattern of HR signals during loading. The model was tested on HR value data of 18 cattle (11 heifers aged 14-16 months and 7 cows aged 2-3 years) and it described the HR profile well. The mean coefficient of determination, R2, was found to be 0.89 + 0.06. The HR rose exponentially from its mean resting value to a peak value (about 1.9 times the value at resting level) and then declined, during a recovery period, to the post-stress level (about 1.15 times the value at resting level). The mean HR at resting condition, peak, and after recovery were 80+6 bpm, 136+35 bpm and 91+19 bpm for heifers and 47+4 bpm, 102+27 bpm, and 55+12 bpm for cows, respectively. The rate of increase in HR (during rising period) was greater than the rate of decrease during the recovery period. In all HR data sets, it was noticed that HR reduced immediately after it attained the peak value
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| 3. |
- Gebresenbet, Girma, et al.
(författare)
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Optimisation analysis of large and small-scale abattoirs in relation to animal transport and meat distribution
- 2011
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Ingår i: Australian Journal of Agricultural Engineering. - 1836-943X. ; 2, s. 31-39
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Tidskriftsartikel (refereegranskat)abstract
- This study reports the optimization analysis made to determine the benefits of establishing a small-scale local abattoir in comparison with the large scale-abattoir in relation to transport distance and time during animal transport and meat distribution, which have a direct impact on animal welfare, meat quality and the environment. Consumer attitudes towards locally produced meat and the self-sufficiency of the region, where the local abattoir was planned to be established, were also examined. It was found that consumers in the region strongly preferred locally produced meat and about 50% of the meat produced would be sufficient to meet demand in the region. Major benefits of having the local abattoir included: (1) Reductions in transport distance and transport time of collecting animals from farms and delivering them to the abattoir by 42% and 37% respectively. The corresponding greenhouse gas (GHG) emissions that were generated from vehicles reduced by 42%. (2) Reductions in transport distance, transport time and GHG emissions involved in distributing meat to the retailers of about 53%, 46% and 53%, respectively. (3) The significant reduction of transport distance and time improves animal welfare
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