Study of springback of green bodies using micromechanical experiments and the discrete element method

The Discrete Element Method (DEM) is today a commonly used tool to simulate compaction of particulate media. The main issue when using DEM in compaction problems is the description of the contact between two powder particles. If the material properties are known, analytical and semi-analytical methods can be used [1,2] but for many industrial applications, for instance spray dried granules, the mechanical behaviour is unknown. The compaction behaviour and green properties of a cemented carbide powder is studied in this work and the issue of the contact description is solved by performing experiments on the powder granules. Firstly, compression tests are made on the single granules giving information of the mechanical properties at low strains. To get information at high strains, which are needed in powder compaction simulations, nanoindentation tests are performed. The measured material parameters are used in a FE model of two spheres in contact and the resulting contact law is exported to a DEM program. The DEM program is used to investigate the compaction properties of a powder compact and especially the springback during unloading which is important for predicting the final shape of the product. The results are compared with presently performed experiments and the applicability range of the discrete element simulations will be discussed

The interdisciplinary decision problem : Popperian optimism and Kuhnian pessimism in forestry

Interdisciplinary research in the fields of forestry and sustainability studies often encounters seemingly incompatible ontological assumptions deriving from natural and social sciences. The perceived incompatibilities might emerge from the epistemological and ontological claims of the theories or models directly employed in the interdisciplinary collaboration, or they might be created by other epistemological and ontological assumptions that these interdisciplinary researchers find no reason to question. In this paper we discuss the benefits and risks of two possible approaches, Popperian optimism and Kuhnian pessimism, to interdisciplinary knowledge integration where epistemological and ontological differences between the sciences involved can be expected.Peer reviewe

DACS: Domain Adaptation via Cross-domain Mixed Sampling

Semantic segmentation models based on convolutional neural networks have recently displayed remarkable performance for a multitude of applications. However, these models typically do not generalize well when applied on new domains, especially when going from synthetic to real data. In this paper we address the problem of unsupervised domain adaptation (UDA), which attempts to train on labelled data from one domain (source domain), and simultaneously learn from unlabelled data in the domain of interest (target domain). Existing methods have seen success by training on pseudo-labels for these unlabelled images. Multiple techniques have been proposed to mitigate low-quality pseudo-labels arising from the domain shift, with varying degrees of success. We propose DACS: Domain Adaptation via Cross-domain mixed Sampling, which mixes images from the two domains along with the corresponding labels and pseudo-labels. These mixed samples are then trained on, in addition to the labelled data itself. We demonstrate the effectiveness of our solution by achieving state-of-the-art results for GTA5 to Cityscapes, a common synthetic-to-real semantic segmentation benchmark for UDA.Comment: This paper has been accepted to WACV202

ClassMix: Segmentation-Based Data Augmentation for Semi-Supervised Learning

The state of the art in semantic segmentation is steadily increasing in performance, resulting in more precise and reliable segmentations in many different applications. However, progress is limited by the cost of generating labels for training, which sometimes requires hours of manual labor for a single image. Because of this, semi-supervised methods have been applied to this task, with varying degrees of success. A key challenge is that common augmentations used in semi-supervised classification are less effective for semantic segmentation. We propose a novel data augmentation mechanism called ClassMix, which generates augmentations by mixing unlabelled samples, by leveraging on the network's predictions for respecting object boundaries. We evaluate this augmentation technique on two common semi-supervised semantic segmentation benchmarks, showing that it attains state-of-the-art results. Lastly, we also provide extensive ablation studies comparing different design decisions and training regimes.Comment: This paper has been accepted to WACV202

Why resilience is unappealing to social science : Theoretical and empirical investigations of the scientific use of resilience

Resilience is often promoted as a boundary concept to integrate the social and natural dimensions of sustainability. However, it is a troubled dialogue from which social scientists may feel detached. To explain this, we first scrutinize the meanings, attributes, and uses of resilience in ecology and elsewhere to construct a typology of definitions. Second, we analyze core concepts and principles in resilience theory that cause disciplinary tensions between the social and natural sciences (system ontology, system boundary, equilibria and thresholds, feedback mechanisms, self-organization, and function). Third, we provide empirical evidence of the asymmetry in the use of resilience theory in ecology and environmental sciences compared to five relevant social science disciplines. Fourth, we contrast the unification ambition in resilience theory with methodological pluralism. Throughout, we develop the argument that incommensurability and unification constrain the interdisciplinary dialogue, whereas pluralism drawing on core social scientific concepts would better facilitate integrated sustainability research.Peer reviewe

The biogenetic law and the Gastraea theory: From Ernst Haeckel's discoveries to contemporary views

More than 150 years ago, in 1866, Ernst Haeckel published a book in two volumes called Generelle Morphologie der Organismen ( General Morphology of Organisms ) in the first volume of which he formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny. Here, we describe Haeckel's original idea as first formulated in the Generelle Morphologie der Organismen and later further developed in other publications until the present situation in which molecular data are used to test the “hourglass model,” which can be seen as a modern version of the biogenetic law. We also tell the story about his discovery, while traveling in Norway, of an unknown organism, Magosphaera planula , that was important in that it helped to precipitate his ideas into what was to become the Gastraea theory. We also follow further development and reformulations of the Gastraea theory by other scientists, notably the Russian school. Elias Metchnikoff developed the Phagocytella hypothesis for the origin of metazoans based on studies of a colonial flagellate. Alexey Zakhvatin focused on deducing the ancestral life cycle and the cell types of the last common ancestor of all metazoans, and Kirill V. Mikhailov recently pursued this line of research further

Annals of the History and Philosophy of Biology 25/2020

The name DGGTB (Deutsche Gesellschaft für Geschichte und Theorie der Biologie; German Society for the History and Philosophy of Biology) reflects recent history as well as German tradition. The Society is a relatively late addition to a series of German societies of science and medicine that began with the “Deutsche Gesellschaft für Geschichte der Medizin und der Naturwissenschaften”, founded in 1910 by Leipzig University’s Karl Sudhoff (1853-1938), who wrote: “We want to establish a ‘German’ society in order to gather German-speaking historians together in our special disciplines so that they form the core of an international society…”. Yet Sudhoff, at this time of burgeoning academic internationalism, was “quite willing” to accommodate the wishes of a number of founding members and “drop the word German in the title of the Society and have it merge with an international society”. The founding and naming of the Society at that time derived from a specifi c set of historical circumstances, and the same was true some 80 years later when in 1991, in the wake of German reunification, the “Deutsche Gesellschaft für Geschichte und Theorie der Biologie” was founded. From the start, the Society has been committed to bringing studies in the history and philosophy of biology to a wide audience, using for this purpose its Jahrbuch für Geschichte und Theorie der Biologie. Parallel to the Jahrbuch, the Verhandlungen zur Geschichte und Theorie der Biologie has become the by now traditional medium for the publication of papers delivered at the Society’s annual meetings. In 2005 the Jahrbuch was renamed Annals of the History and Philosophy of Biology, reflecting the Society’s internationalist aspirations in addressing comparative biology as a subject of historical and philosophical studies

Development of a conceptual framework for integrated analysis and assessment of agricultural systems in SEAMLESS-IF

Production Economics,