Analysis of Inter-particle Contact Parameters of Garlic Cloves Using Discrete Element Method

Purpose The discrete element method (DEM) can be used in agricultural fields such as crop sowing, harvesting, and crop transportation. Nevertheless, modeling complex crops as appropriately shaped particles remains challenging. The modeling of particles and the calibration of input parameters are important for simulating the realistic behaviors of particles using the DEM. Methods In this study, particle models representing the morphological characteristics and size deviations of garlic cloves were proposed. Additionally, the coefficients of friction were analyzed as the contact parameters of the particles based on the heap formation experiments and simultations of the swing-arm method using 150 garlic cloves. Results The simulation results were analyzed that the residual number of particles, a bulk property that can be measured simply in the experiment, is related to the coefficients of friction. In the heap formation experiments with low particle counts, the bulk properties were more clearly differentiated by the residual number of particles than the angle of repose. Moreover, the bulk properties similar to the actual garlic could not be expressed as a spherical particle model. Thus, an equation for predicting the residual number of particles was derived for the non-spherical garlic clove particle model. Five sets of coefficients of friction were presented using the prediction equation, and all the simulation results were close to the actual residual number of particles and angle of repose of the garlic. Conclusions Although the sizes of garlic cloves have a wide distribution, appropriate inter-particle contact parameters could be predicted. Therefore, the calibration process of the DEM can be shortened using the proposed prediction equation for the residual number of particles with non-spherical particles.

IMPACTOS DA COVID-19 NO SETOR CULTURAL PORTUGUÊS: como é que os 308 municípios reagiram à pandemia?

O POLOBS encontra-se a desenvolver uma pesquisa que visa identificar e analisar alguns dos impactos da COVID-19 no setor cultural português. O projeto, que conjuga uma abordagem qualitativa com uma abordagem quantitativa, e integra instrumentos e técnicas diversificadas, iniciou-se a 16 de março de 2020 e vai decorrer até 31 de março de 2021.No presente artigo vamos lançar um olhar sobre seis meses de notícias nos 308 municípios portugueses. A análise efetuada permite-nos afirmar,ainda que provisoriamente, queo fluxo de notícias nos websites dos municípios está em linha com o pouco peso estratégico que a cultura tem em muitas das dinâmicas das políticas municipais, tendo sido possível identificar um número residual de medidas das autarquias locais para a mitigação, a curto e médio prazos, dos impactos negativos nas organizações e profissionais do setor cultural.IMPACTS OF COVID-19 ON THE PORTUGUESE CULTURAL SECTOR: how did the 308 municipalities react to the pandemic?AbstractPOLOBS is conducting a research that focuses on the identification and examination of some of the impacts of COVID-19 on the Portuguese cultural sector. Beginning on the 16th of March 2020 and ending on the 31st of March 2021, this project combines qualitative and quantitative approaches and accommodates different tools and techniques. In this article we are going to take a look at six months of news in the 308 Portuguese municipalities. The analysis carried out allows us to affirm, even provisionally, that the flow of news on the websites of the municipalities is in line with the little strategic weight that culture has in many of the dynamics of municipal policies, and it was possible to identify a residual number of measures of the local authorities to mitigate, in the short and medium term, the negative impacts on organizations and professionals in the cultural sector.Keywords: COVID-19. Culture. Impacts. Portuguese municipalities

People: From a Collection Manager's Viewpoint

The specimens held in natural history collections around the world are the direct result of the effort of thousands of people over hundreds of years. However, the way that the names of these people have been recorded within the collections has never been fully standardised, and this makes the process of correctly assigning the event relating to the specimen to an individual difficult at best, and impossible at worst. The events in which people are related to specimens include collecting, identifying, naming, loaning and owning. Whilst there are resources in the botanical community that hold information on many collectors and authors of plant names, the residual number of unknown people and the effort required to disambiguate them is daunting. Moreover, in many cases, the work carried out within the collection to disambiguate the names relating to the specimens is often not recorded and made available, generally due to the lack of a system to do so. This situation is making it extremely difficult to search for collections within the main aggregators, such as GBIF —the Global Biodiversity Information Facility— , and severely hampers our ability to link collections both within and between institutes and disciplines. When we look at benefits of linking collections and people, the need to agree and implement a system of managing people names becomes increasingly urgent.