The discharge rate of coarse powders (mean particle size >500 pm) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradient develops near the hopper outlet, inducing an air flow into the hopper. This extra drag force ...

Prior studies at Purdue University have shown that PTO entanglements occur most frequently on portable grain augers. A research project was conducted to measure operator exposure to PTO components and document work patterns during the use of grain augers. Information on the methodologies used to measure operator exposure is presented along with data on exposure to conventional grain augers whil...

The paper presents the development of dynamic domain decomposition applied to hopper discharge simulation by the discrete element method (DEM). Parallel neighbour search algorithm, non-blocking interprocessor communication and dynamic load balancing are implemented in the DEM code. Parallel speed-up analysis is performed solving the complex hopper discharge problems containing 100000 and 300000...

organic manure plays an important role in the improvement of soil structure by decreasing bulk density and increasing porosity. however, the method of manure spreading influences its beneficial impact on soil structure. in this study, a novel helical manure distributor machine capable of spreading manure with different moisture contents at maximum distribution width was developed and the machin...

Many high-throughput analytical platforms, from next-generation DNA sequencing to drug discovery, rely on beads as carriers of molecular diversity. Microfluidic systems are ideally suited to handle and analyze such bead libraries with high precision and at minute volume scales; however, the challenge of introducing bead suspensions into devices before they sediment usually confounds microfluidi...

1. As species are often considered discrete natural units, interspecific sexual interactions are often disregarded as potential factors determining community composition. Nevertheless reproductive interference, ranging from signal jamming to hybridization, can have significant costs for species sharing similar signal channels. 2. We combined laboratory and field experiments to test whether the ...

This paper presents an approximate solution to the flow of a cohesionless granular material in a conical hopper. This is a problem which has received considerable attention in the past though much of the work was directed toward developing an empirical relation of the mass flow rate from experimental data (for example (1,211. In the early 1960's Jenike and Johanson [23] applied the basic princi...

Locust swarms cause famine and hunger in parts of Sub-Saharan Africa as they travel across croplands and eat vegetation. Current models start with biological properties of locusts and analyze the macroscopic behavior of the system. These models exhibit the desired migratory behavior, but do so with too many parameters. To account for this, a new model, the Alignment and Intermittent Motion (AIM...

In this paper, we describe modeling and control techniques to accurately representing a real-world series-elastic actuated 1D hopping robot. There is an abundance of work regarding the implementation of highly simplified hopper models, with the hopes of extracting fundamental control ideas for running and hopping robots. Accurately controlling a nonlinear system such as the hopper depends on a ...