John M. Fielke

Comparison of tillage forces and wear rates of pressed and cast cultivator shares

Abstract The draft force, vertical up force and wear rate of 5-mm-thick pressed steel shares were compared with those of 10-mm-thick cast steel shares. The tests were conducted using a range of soil types and moisture contents over several years. Because they were made of a harder material, the cast shares lost mass at 0.48 of the rate of the pressed shares, irrespective of the soil type or condition. However, the cast shares, because they were made from thicker material, had a blunter cutting edge which in moist soil conditions increased the draft and vertical up forces. The results showed the wear rate (based on distance) to be independent of the speed of tillage but the soil type and condition had a large effect on the wear rates and tillage forces.

Conditioning reduces kernel damage when impact shelling almonds

Abstract Almonds can be classified based on their shell characteristics from soft to hard shell varieties. The majority of Australian and Californian varieties have soft shell properties. Most Spanish almond varieties have hard shells. Although having a hard sealed shell protects the kernel from insect damage it affects their processability. Common commercial almond processing equipment simultaneously compresses and shears the almonds and this creates a high percentage of damaged kernels from the broken shell being forced into the kernel, particularly for hard shell varieties. This paper shows that for the soft shell variety ‘Nonpareil’ and the three hard shell varieties of ‘Marcona’, ‘Tarraco’ and ‘Vyro’ that conditioning by soaking in water and resting before processing improves the recovery of undamaged kernel when shelling using impact. The impacts were applied by feeding the almonds into a rotating impellor and throwing them onto a stationary outer wall. An effective conditioning process resulted in the kernel moisture content increasing from 6% to 14% for hard shell and to 11% for ‘Nonpareil’ varieties. The conditioning process was measured to reduce the amount of scratched, chipped and broken kernel, and hence increased the recovery of undamaged kernel. After shelling, the conditioned kernel needed to be dried back to a 6% moisture content to be suitable for storage. Hence, the industry would be able to increase its recovery of undamaged kernel by changing to an impact shelling process using suitably conditioned almonds.

Recent developments in stored grain sensors, monitoring and management technology

Up to one third of the total annual global production of grain (cereals, oil seeds, and pulses) is lost primarily due to poor post-harvest management. Lack of control over grain moisture content, temperature and insect infestations are the three most significant factors causing this loss. High grain moisture and temperature provide favorable conditions for hotspot development, mold growth, and insect infestation. Recent technological advancements in grain storage condition monitoring and control (both hardware and software) are now helping to safely store grain for periods of several years with minimal quality loss.

Application of Power Spectral Density to Recognise the Important Factors Creating Tractor-Subsoiler Vibrations

Abstract A deep working oscillatory subsoiler was developed at the University of South Australia to be towed by a tractor (3 t and 70 kW) in a semi-mounted configuration. During use, the soil-tool interaction forces transferred too much vibration to the tractor when operating at the desired subsoiler settings. In order to reduce the tractor vibrations, the source of vibration was studied using the power spectral density method to correlate the tractor seat vibrations to machine operating parameters. It was found that tyre lug engagement and the engine speed did not have significant effect on tractor vibration. The soil-tool interaction of both soil cutting and compaction during the oscillating motion of the tine, combined with the torque peaks on the driveline from the power take-off to the tines, had the dominant effect on vibration.