Ecological restoration of grasslands using wild-collected seeds is a major undertaking in many parts of the world. Impediments to effective seed use such as low seed quality, difficult-to-handle and bulky collections of seeds, and seed dormancy and germination constraints contribute to restoration failure. Native grass florets are typically irregular in shape, with appendages that impede efficient mechanized sowing and render agricultural technologies, such as the application of polymer seed coatings, impractical. Our goal was to investigate the application of a novel flaming device to remove floret appendages and improve geometry using Triodia wiseana (C.A. Gardner [Poaceae]), a key framework grass of arid ecosystems in north-western Australia, as a test species. Through the modification of a rotary seed coater with an engineered flaming apparatus, a flash flaming technique was developed. We demonstrate that flash flaming is a highly effective and efficient means of removing floret appendages and subsequently improving geometry. Once flamed, the bulk density of florets was significantly increased, the application of polymer coatings was more effective, and germination was enhanced. The improved floret geometry through flaming therefore shows promise for enhancing the mechanization of direct seeding of grasses. Implications for Practice• Grass floret appendages complicate the handling of large quantities of seeds. • Grass florets are typically extremely irregular in shape and have appendages that impede efficient use; these complicate the application of seed coatings and often make mechanized direct seeding impractical. • The application of a novel flaming technique to Triodia wiseana florets demonstrated its potential to be an effective and efficient way of removing appendages from this key framework grass of arid ecosystems in north-western Australia.

When developing vibration models, so as to reduce model complexity, it is typically expected that good prediction accuracy can be achieved by ignoring the complication of friction. In this paper, the significance of friction between the piston and cylinder on engine block dynamics is shown through simulation in both the time and frequency domains. Simulations and experiments indicate that large differences exist between model predictions for the engine block moment if this friction is not accounted for. This is especially true at low crankshaft rotational speeds when dynamic inertia effects are small. Experiments on a motored single cylinder engine at different average rotational speeds confirm the theory and very good tie-up with predictions is obtained. It is expected that these findings will also have implications for the torsional vibration of the engine.

In order to obtain greater accuracy in simulation, more sophisticated models are often required. When it comes to the torsional vibration of reciprocating mechanisms the effect of inertia variation is very important. It has been shown that the inclusion of this variation increases model accuracy for both single-cylinder and multi-cylinder engine torsional vibration predictions. Recent work by the present authors has revealed that piston-to-cylinder friction may modify an engine's ‘apparent’ inertia function. Kinematic analysis also shows that the piston side force and the dynamic piston-to-cylinder friction are interdependent. This has implications for engine vibration modelling. Most modern engines employ a gudgeon pin offset, and there is a growing interest in pursuing large crank offsets; hence, the effect of these on inertia variation is also of interest. This paper presents the derivation of the inertia function for a single engine mechanism, including both piston-to-cylinder friction and crank or gudgeon pin offset, and investigates the effect of each through predictions. The effect of crank offset on the variable inertia function is also verified by experiment.

Mine rehabilitation is not just earthworks. Mine rehabilitation is a complex, integrated process that involves multiple stakeholders, long-term commitment, and a comprehensive understanding of site-specific conditions. When it comes to the re-introduction of vegetation, increasing the likelihood of successful plant establishment requires the proper implementation of many components including growth media movement, land forming, seedbed preparation, and seed delivery. From a perspective of initiating plant recruitment, best practice use of native seeds is fundamental, and seed technologies can also be coupled with the invention, development and modification of the seeding equipment needed to deliver seeds at scale. Improving seed-use efficiency through seed-enhancement technologies is one approach that has gained recent attention in dryland rehabilitation. Techniques including precision flash flaming, priming, polymer-based seed coating, and extruded seed pelleting all aim to improve the germination and establishment potential of seeds under suboptimal conditions. Along with modifications to existing mechanical seeders or with new builds, these technologies are one potential solution to overcome inefficiencies in dryland seeding efforts. For instance, through the fabrication and engineering of new parts fitted to existing seed-coating equipment, 'flash flaming' is a technique that removes unwanted hairs and appendages off bulky and fluffy seed batches (e.g. spinifex or Triodia species). After removal, seed batch volume is significantly reduced, while the flow properties of seeds through cleaning equipment and mechanised seeders are vastly improved.

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The methods used to distribute seeds influence the success of a restoration project. We surveyed 183 restoration practitioners from across the globe with the aim of identifying common limitations to the effective use of mechanical direct seeding in large‐scale restoration practice to highlight avenues for design improvement to mechanized seeding equipment. Results from this survey show that direct seeding methods are commonly used for ecological restoration and agree with other studies that suggest the method can achieve results much quicker and cheaper than the alternative of distributing nursery‐grown tube stock. However, this study indicates that current mechanical direct seeding methods lack adequate control of seed sowing depth and spatial distribution and highlight that the inability to sow seeds of varying morphology over complex topography are common limitations to direct seeding. To improve restoration success, engineering improvements to mechanical direct seeders used in large‐scale restoration should focus in particular on addressing issues of precision of delivery for diverse seed types and landscapes.

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