Increase of paddy moisture with automatic aeration in a warehouse guided by adsorption equilibrium absolute humidity equation: Poster

An automatic bulk monitoring and aeration controller was programmed with an adsorption equilibrium absolute humidity (CAE)equation and was used to aerate paddy with the aim to increase moisture content (MC) and preventing fissuring. The ventilation control window for rewetting paddy was developed according to two conditions: (i) the average grain bulk temperature (t<sub>g</sub>) is higher than the dewpoint temperature (DPT<sub>a</sub>) of the atmosphere; and (ii) the equilibrium absolute humidity (EAH<sub>g</sub>) of grain moisture content plus 1 percentage point is lower than the absolute humidity (AH<sub>a</sub>) of the atmosphere. The ventilators were turned on when the atmosphere state point was within the ventilation windowand turned off outside that window. In a humid subtropical monsoon climate, during Oct. 8<sup>th</sup> to Nov. 1<sup>st</sup>, 2013, the system was used for a paddy depot of 1035 t in Dianjiang, Chongqing province. The natural humid air was introduced into the paddy bulk by negative pressure suction aeration during the 10-12 h night time period and allowed to equilibrate with grain kernels during the 12-14 h day time period. Aeration increased grain MC by 0.6 percentage points with two 1.5 kW axial flow ventilators and power consumption of 209 kW·h. The unit energy consumption was 0.336 KW·h (1% moisture·t)<sup>-1</sup>. The broken milled rice percentage was decreased by 2-3 percentage points. In the warm temperate semi-humid monsoon climate, during April 13<sup>th</sup> to June 16<sup>th</sup>, 2017, the system was used to rewet japonic paddy in a 2489 t depot in Qihe, Shandong province. The conditions for running two 0.85 kW axial flow fans were: (i) when the atmosphere relative humidity (RH<sub>a</sub>) is =80% and its temperature (t<sub>a</sub>) is <28°C, t<sub>g</sub>>DPT<sub>a</sub>, and EAH<sub>g</sub><AH<sub>a</sub>; and (ii) when RH<sub>a</sub> >80% and t<sub>a</sub> <28°C. Whenever t<sub>a</sub> was >28°C, the two fans were switched off. This rewetting aeration increased grain MC from 13.5% to 14.0%, and the unit energy consumption was 0.455 kW·h (1% moisture·t)<sup>-1</sup>. The percentages of average head rice yield and damaged grains after aeration were 71.7% and 7.7%, respectively.An automatic bulk monitoring and aeration controller was programmed with an adsorption equilibrium absolute humidity (CAE)equation and was used to aerate paddy with the aim to increase moisture content (MC) and preventing fissuring. The ventilation control window for rewetting paddy was developed according to two conditions: (i) the average grain bulk temperature (t<sub>g</sub>) is higher than the dewpoint temperature (DPT<sub>a</sub>) of the atmosphere; and (ii) the equilibrium absolute humidity (EAH<sub>g</sub>) of grain moisture content plus 1 percentage point is lower than the absolute humidity (AH<sub>a</sub>) of the atmosphere. The ventilators were turned on when the atmosphere state point was within the ventilation windowand turned off outside that window. In a humid subtropical monsoon climate, during Oct. 8<sup>th</sup> to Nov. 1<sup>st</sup>, 2013, the system was used for a paddy depot of 1035 t in Dianjiang, Chongqing province. The natural humid air was introduced into the paddy bulk by negative pressure suction aeration during the 10-12 h night time period and allowed to equilibrate with grain kernels during the 12-14 h day time period. Aeration increased grain MC by 0.6 percentage points with two 1.5 kW axial flow ventilators and power consumption of 209 kW·h. The unit energy consumption was 0.336 KW·h (1% moisture·t)<sup>-1</sup>. The broken milled rice percentage was decreased by 2-3 percentage points. In the warm temperate semi-humid monsoon climate, during April 13<sup>th</sup> to June 16<sup>th</sup>, 2017, the system was used to rewet japonic paddy in a 2489 t depot in Qihe, Shandong province. The conditions for running two 0.85 kW axial flow fans were: (i) when the atmosphere relative humidity (RH<sub>a</sub>) is =80% and its temperature (t<sub>a</sub>) is <28°C, t<sub>g</sub>>DPT<sub>a</sub>, and EAH<sub>g</sub><AH<sub>a</sub>; and (ii) when RH<sub>a</sub> >80% and t<sub>a</sub> <28°C. Whenever t<sub>a</sub> was >28°C, the two fans were switched off. This rewetting aeration increased grain MC from 13.5% to 14.0%, and the unit energy consumption was 0.455 kW·h (1% moisture·t)<sup>-1</sup>. The percentages of average head rice yield and damaged grains after aeration were 71.7% and 7.7%, respectively

Particle Size Effect on DEM Simulation of Pressures Applied on a Cylindrical Silo with Hopper

This work is a contribution to the comprehension of the particle upscaling effect on DEM simulation of cylindrical silos. Three silo models have been simulated with different hopper outlets and inclination angles. Huge calculations of 11 simulation series with a different scaling factor are considered for every model. Pressures applied on silo walls remain quite identical with particle upscaling. Besides, their curves are in agreement with Eurocode standard. The computing time is significantly reduced as well as the number of particles, where the simulation speed is increased up to 12 times by just scaling particle radius two times. The total bulk density was not affected by particle escalation and its value remains unchanged

Modelling of Silo Loads under eccentric Discharge

Silobauwerke weisen hohe Schadensraten auf. Besonders bei Silos mit exzentrisch angeordneter Auslauföffnung stellt die Bemessungssituation für die planenden Ingenieure immer noch eine Herausforderung dar. Das Ingenieurmodell nach Rotter für die Entleerung von Silos mit großen Exzentrizitäten, das in der aktuellen Norm Anwendung findet, wurde unter Anwendung der Scheibenelementmethode nach Janssen entwickelt. Der auf vereinfachten Annahmen beruhende Ansatz hat sich in der Ingenieurpraxis als unzulänglich erwiesen. Daher ist eine genaue Erfassung der unsymmetrischen Belastungen von Silokonstruktion für eine wirtschaftliche und sichere Auslegung von vitalem Interesse. Die Modellierung eines Schüttgutes gilt immer als große Herausforderung in der Numerik. Die Gründe dafür sind zum einen, dass mit einer großen Verformung zu rechnen ist, wenn das Schüttgut in Bewegung ist. Dies führt in der herkömmlichen FEM, basierend auf der Lagrangeschen Formulierung, zu Schwierigkeiten. Zum anderen ist die Beschreibung des nichtlinearen Materialverhaltens eines Schüttgutes sehr komplex. In dieser Arbeit werden mit Hilfe neuer numerischer Methoden die Entleerungsvorgänge in Silos simuliert, womit eine längere Entleerungszeit und somit der stationäre Zustand erreicht wird. Die Simulationsergebnisse stimmen sehr gut mit den Versuchsergebnissen überein. Dabei stehen die berechneten Wanddrücke in großem Kontrast zu den nach der Norm berechneten Werten. In DIN EN 1991-4 wird lediglich das Fließprofil eines Schlotflusses parallel zur Silowand berücksichtigt. Das numerisch ermittelte Fließprofil für Weizen zeigt ein gemischtes Fließen und für Sand einen inneren Schlotfluss, dessen Fließkanalgrenze sich bis zur Schüttgutoberfläche erstreckt. Dahingehend werden aktuell in der DIN EN 1991-4 keine Unterscheidungen gemacht und es bedarf damit einer Berücksichtigung. Stabilitätsuntersuchungen mit den simulierten Lasten und den Normlasten zeigen, dass die Tragfähigkeit von Silos bei exzentrischer Entleerung nach dem Normansatz deutlich unterschätzt wird. An einem Silo wird die Auswirkung des neuen Ansatzes auf die Bemessung untersucht, dabei zeigen die Berechnungen mit dem neuen Ansatz gegenüber dem Normansatz für die drei Beulsicherheitsnachweise eine wesentlich bessere Abbildung des realen Tragverhaltens auf. Des Weiteren kann ein Silo mit dem Ansatz aufgrund seiner einfachen Handhabung sowohl wirtschaftlich als auch sicher ausgelegt werden.Silo structures tend to comprise high damage rates. Especially silos with an eccentrically arranged outlet still imply a major challenge for the planning engineers in the process of the design situation. The engineering model by Rotter for highly eccentric discharge, which is applicable within the current European Standard EN 1991-4 (2010), was developed using the slice element method of Janssen. However, the approach based on simplified assumptions turned out to be deficient in engineering practice. Thus, an accurate description of the asymmetric loads of silo constructions is of vital interest for a safe and economic design. The modelling of bulk material is always considered as a major challenge in numerical analysis.The reasons on the one hand are that there is likely to be a great distortion when the bulk material is in motion. This leads to difficulties within the conventional FEM based on the Lagrangian formulation. On the other hand, the specification of non-linear material behavior of bulk material is very complex.Within this thesis, the emptying processes are simulated with the help of new numerical methods, which consequently leads to a longer discharge process and a stationary state is therefore reached. The simulation results show good correlation to the test results. Hence, the calculated wall pressures are contrary to the calculated values considering the standard. DIN EN 1991-4 only considers the flow profile of a chimney flow parallel to the silo wall. The numerically determined flow profile for wheat shows a mixed flow and for sand an eccentric taper pipe flow, whose flow channel boundary ranges up to the bulk material surface. However, no distinctions are currently made within the DIN EN 1991-4, which requires further consideration. Stability investigations with the simulated loads and the standard loads implicate that the load capacity of silos under eccentric discharge according to the standard are being significantly underestimated, the calculations using the new approach compared to the standard approach considering the there design concepts for the verification of shell stability show a considerably improved reflection of the real structural behavior. Furthermore, due to its ease of use, this approach enables a safe and economic design of a silo

Space Exploration Robotic Systems ¿ Sample Chain Analysis and Development for Enceladus Surface Acquisition

L'abstract è presente nell'allegato / the abstract is in the attachmen

Proceedings of the European Conference on Agricultural Engineering AgEng2021

This proceedings book results from the AgEng2021 Agricultural Engineering Conference under auspices of the European Society of Agricultural Engineers, held in an online format based on the University of Évora, Portugal, from 4 to 8 July 2021. This book contains the full papers of a selection of abstracts that were the base for the oral presentations and posters presented at the conference. Presentations were distributed in eleven thematic areas: Artificial Intelligence, data processing and management; Automation, robotics and sensor technology; Circular Economy; Education and Rural development; Energy and bioenergy; Integrated and sustainable Farming systems; New application technologies and mechanisation; Post-harvest technologies; Smart farming / Precision agriculture; Soil, land and water engineering; Sustainable production in Farm buildings