On the flow characteristics of the conical Minoan pipes used in water supply systems,via computational fluid dynamics simulations

The Minoan Terracotta pipes with their conical shape were widely used in the water distribution system in the ancient Minoan civilization. They remain one of the brightest achievements of the Minoan tribe in water supply technology and raise admiration as well as many questions about the technological advancements of antiquity, that are yet to be understood. The present work aims at answering the following questions: a) what inspired the Minoans to manufacture pipes with such a peculiar shape, that differs greatly not only from later pipe designs of antiquity, but also from contemporary cylindrical pipes and b) why was the design of those pipes abandoned after the fall of the Minoan civilization? It tries to address these questions by investigating the flow physics and dynamics that take place in such pipes, adopting advanced numerical and computational methods. The time-averaged Navier–Stokes equations along with the k − ? turbulence model are solved for a variety of geometrical parameters, pipe orientations and flow rates, in order to produce a comparative picture of the hydraulic efficiency of the conical Minoan pipes. The flow field is visualized and critical flow parameters, such as the head loss, the velocity magnitude and turbulence intensity, are calculated. These calculations show clearly that the conical Minoan pipes exhibit significantly higher pressure drops along their length compared to an equivalent straight pipe. In their widest part an extended recirculation appears, which could wash out impurities that may be present in the water, which at the same time cannot be deposited on the pipe wall. This evidence proves that the Minoan pipes are energetically expensive to operate and consequently their replacing by cylindrical pipes was inevitable. Therefore, it seems that the main advantage and purpose of the particular geometry was that they could be easily connected on site, forming long straight or slowly bending lines without having to add straight or many different fittings in between.     

Physik und Politik in der frühen Bundesrepublik Deutschland. Max Born,Werner Heisenberg und Pascual Jordan als politische Grenzgänger

Physics and Politics in the Early Federal Republic of Germany. Max Born, Werner Heisenberg and Pascual Jordan between Scientific and Political Discourse. – Contrasting the historiography of two major developments in 20th century German history, the creation of quantum mechanics in 1925 and the dispute on the nuclear armament of the Federal Republic of Germany in 1957, the question is raised to which extent the scientific culture was able to bridge political disagreement within the German physicists' community. A twofold story of the private and public exchange between Max Born, Werner Heisenberg and Pascual Jordan among others on the scientists' position to nuclear armament on the one hand and the writing of the history of quantum mechanics on the other hand displays different types of relating scientific work and moral responsibility. Neither politics nor science went on unaltered after the disputes between physics and politics in the early Federal Republic of Germany.     

The Statistical Style of Reasoning and the Invention of Bose‐Einstein Statistics

This paper is a preliminary exploration of the connections between the statistical style of reasoning and the research practices of statistical mechanics in the early period of the long quantum revolution. It suggests that before 1925 the instantiations of the statistical style in physics went through two phases. The first phase consisted of the formulation of the Maxwell‐Boltzmann statistics on the basis of the population‐gas analogy. The second phase was characterized by the generalization of the Maxwell‐Boltzmann statistics through analogies between ideal gas molecules and other microphysical entities, analogies that shaped and were shaped by the rise of quantum theory. Einstein's invention of the Bose‐Einstein statistics started a third phase and created the conditions of possibility for a new classification of microphysical entities according to their different statistics.     

Vein quartz in lithic traditions: an analysis based on experimental archaeology

Worldwide, vein quartz was a commonly used raw material for stone tools but this material has proved difficult for archaeologists to analyse because many quartz assemblages appear to be comprised of amorphous pieces, not easily recognised as humanly modified or forming ‘tools’. This paper discusses the analysis of the debitage – focusing on the debitage fragmentation rate, the debitage, break, and fragment types, and the quantitative analysis of the complete flakes – resulting from experimental knapping of quartz, which formed part of a project which investigated the use of quartz in Irish prehistoric lithic traditions. The results have highlighted the complexity involved in analysing quartz assemblages, and the significant differences between the debitage products of quartz and chert knapping assemblages. While bipolar knapping is generally easy to differentiate from direct percussion, it is harder to differentiate between soft and hard hammer percussion.     

Beyond Ideology: Epistemological Foundations of Vladimir Fock's approach to Quantum Theory

Vladimir Fock was a Soviet theoretical physicist who, from the 1930s, worked to prove that modern physics was compatible with the Marxist philosophy of dialectical materialism. In 1957, he went to Copenhagen, and a dispute over the interpretation of quantum mechanics began with Niels Bohr. Fock later claimed that he had found points of convergence with his Danish colleague, most of them concerning issues of wording and recognition of the reality of the world independently of our mind. It led to a specific narrative among historians of physics on Fock and his interpretation of quantum mechanics: The Soviet physicist is often described as a member of the Copenhagen school that contributed to the rapprochement of the Soviet philosophy of physics with the ideas of complementarity in stripping away the positivism in its formulation. Our contribution aims to show that this ideological dimension was only one aspect of reality. Returning to the foundations of Fock's epistemology of physics, we argue that he relied on the principles of antireductionism and scientific realism to develop an interpretation of the theory that sought to overcome Bohr's approach and that the differences between the two men cannot be reduced to mere questions of formulation.     

Convergence in Cold War Physics: Coinventing the Maser in the Postwar Soviet Union

At the height of the Cold War, in the 1950s, the process of parallel invention of masers and lasers took place on the opposing sides of the Iron Curtain. While the American part of the story has been investigated by historians in much penetrating detail, comparable Soviet developments were described more superficially. This study aims at, to some extent, repairing this discrepancy by analyzing the Soviet path towards the maser from a comparative angle. It identifies, on the one hand, significant differences between the two projects regarding their heuristics, the relationship between theory and experiment, grounding in different academic cultures, and the resulting conceptualization of the maser principle. At the same time, the case also illustrates more fundamental transformations in the practices of postwar research that can be characterized as a convergence between the Soviet and the American science of the period.     

SIMULATION OF THE CYCLIC BEHAVIOUR OF R/C RECTANGULAR HOLLOW SECTION BRIDGE PIERS VIA A DETAILED NUMERICAL MODEL

In the search for robust constitutive models suitable for reproducing the performance of bridge piers during a seismic event, this paper details the simulation of the cyclic responses of four rectangular hollow section R/C bridge piers. These four R/C bridge piers were built at scale 1/2.5 and tested experimentally. Both tall and short piers are considered, covering situations where bending or shear are of relevance. Furthermore, the four piers were reinforced according to rather different design strategies: (I) the first is a 30-year-old bridge designed without allowance to the seismic action, and (ii) the second is a bridge fulfilling the EC8 provisions. The detailed constitutive model that provides the numerical predictions includes two submodels: one with two scalar damage variables, reproducing the tensile and compressive degradations of concrete, and the other is based on the Giuffre-Menegotto-Pinto formulation, simulating the cyclic behaviour of the re-inforcement. The Damage Mechanics submodel is implemented at the Gauss points of the finite elements that discretize the concrete, whereas the steel submodel is implemented on the 2-noded truss elements adopted for the rebars. A comparison between the numerical and the experimental results is discussed in detail in this paper.     

Decoherence, Quantum Theory and their Implications for the Philosophy of Geomorphology

Recent philosophical discussions on the nature of geomorphology ( Bassett 1994 ; Richards 1994 ; Rhoads 1994 ) have concluded that the way forward in geomorphological explanation is through either an empiricist or a realist approach. This paper draws lessons from quantum mechanics and the related concepts of decoherence and entanglement to explore the theoretical limitations of both of these existing approaches to geomorphology. It is suggested that empiricist and realist approaches are misguided in their attempts to view the researcher as being in some way 'detached' from the reality of the environmental system under investigation. Instead, this reality is viewed here as being consciousness-dependent. The paper also challenges the claims to represent 'truth', and the deterministic view of causation, which are inherent within empiricist and realist approaches. It concludes by suggesting that an idealist approach to geomorphology – one that recognizes the primacy of consciousness – can better appreciate the unpredictable and probabilistic nature of the world.