Insights in thixotropic concrete pumping by a Poiseuille flow extension

Thixotropy is a reversible time-dependent phenomenon in fluids, in which an internal structure grows due to flocculation and breaks down under shear action. Numerous fluids are thixotropic, e.g. concretes and cementitious suspensions. Pumping of concrete is an important application. Since current approaches omit thixotropic effects, we aim to develop a simple theoretical model to evaluate or understand the significance of thixotropy on the concrete pumping behaviour. We therefore extended Poiseuille flow for thixotropic concretes and reformulated it in a dimensionless form to gain insights. After a validation, the results and significance are elaborated and concluded.Results showed that for increasing thixotropy and decreasing flow rates, the plug radius, wall shear rate and pumping pressure loss increase. Even though all thixotropy mechanisms may not be covered, a simple model is delivered to interpret or predict the effect of thixotropy on the pumping behaviour of cementitious suspensions. The dimensionless formulations via the Bingham number Bn and related discharge diagrams are sufficiently elegant for computational implementation and very insightful to distinguish a thixotropic flow regime. The model could be extended for more complicated thixotropies, irreversible time-dependent effects or even other pumping related phenomena.

Trajectory of local farmers on the institutional change level of agricultural land in the agrotourism zone

The research offers a thesis to view the context of land institutional change of agriculture as a factor in local farmer identity formation. The goal is to reject the general idea that always presents a thesis that the change of land institutional has always had a bad impact for farmers. To achieve the research objectives, researchers used Giddens concept the Trajectory of Self, using qualitative methods and phenomenological approaches. This research is focused on the region of Agrotourism in Indonesia, with the technique of observation data collection, in-depth interview, Transect Walk, focus group discussion (FGD), as well as secondary data analysis. The results showed that Dutch colonialization in agriculture became the first phase creation of modernity on land, as land. This condition, which formed a self-development of local farmers, is unconsciously organized and reflective on globalization flows. Thus, creating an institutional that is reversible time, which is a long term and reversible conditioning in spacetime In the form of social activities that are patterned in continuity of daily living and then form the identity of local farmers.

Rethinking the time’s arrow: Beginnings and the sociology of the future

This article asks: What is, sociologically speaking, a beginning? And why has sociology so relatively little to say about beginnings, that point of discontinuity between past meaning and future meaning? We answer these questions in four successive steps. First, we suggest that the existing literature on beginnings can be organized in light of Lévi-Strauss’ distinction between the irreversible time of social practices and the reversible time of analytic models. We use this distinction in the next two sections as we review existing approaches on beginnings. The next section discuss works that have studied beginnings from the perspective of irreversible time. The following section analyses approaches that centre on the perspective of the reversible time of the observer, that collapse the two, or that distinguish them in purely methodological grounds. Building upon the foregoing, we advance a sociological conception of beginnings as a future-oriented duration involving a non-linear succession of temporalities.

Transdisciplinarity across the Qualitative and Quantitative Science through C.S. Peirce’s Semiotic Concept of Habit

This paper investigates how Peirce manages to establish a transdisciplinary fallibilist view of the sciences that is not hostile to religious spirituality viewed as a complementary fallibilist knowledge type. I focus on Peirce’s attempt to construct an alternative to classical mechanical ontology with its reversible time concept and the ontological view of absolute transcendental laws of nature. His triadic semiotic pragmaticism has empiricism in common with the logical positivists, but it shares the fallibilist critical stance with Popper, with whose critical rationalism Peirce also shares a thorough-going evolutionary approach. With Hegel and Schelling, Peirce shares a kind of evolutionary objective idealism and with Whitehead a thoroughgoing process view, and finally with Wittgenstein, he shares a pragmatic view of the meaning of words and concepts. What knits together all these apparently incompatible views is his dynamic Tychism and his Synechist field view. Together these produce a transdisciplinary irreversible view of habits as “laws” of nature, mind, and society that emerge in the development of the cosmos. Though Peirce is somehow close to Hegel’s phenomenological and dialectical view on cosmogony, a number of aspects are quite unique about his approach: the most important of these are his dynamic triadic categorically-based semiotics that makes him understand human beings as well as the universe as symbolic self-organizing developing processes. This is an interesting alternative to modern mechanical info-computationalism.

Toolbox for reconstructing quantum theory from rules on information acquisition

We develop an operational approach for reconstructing the quantum theory of qubit systems from elementary rules on information acquisition. The focus lies on an observerOinterrogating a systemSwith binary questions andS's state is taken asO's `catalogue of knowledge' aboutS. The mathematical tools of the framework are simple and we attempt to highlight all underlying assumptions. Four rules are imposed, asserting (1) a limit on the amount of information available toO; (2) the mere existence of complementary information; (3)O's total amount of information to be preserved in-between interrogations; and, (4)O's `catalogue of knowledge' to change continuously in time in-between interrogations and every consistent such evolution to be possible. This approach permits a {\it constructive} derivation of quantum theory, elucidating how the ensuing independence, complementarity and compatibility structure ofO's questions matches that of projective measurements in quantum theory, how entanglement and monogamy of entanglement, non-locality and, more generally, how the correlation structure of arbitrarily many qubits and rebits arises. The rules yield a reversible time evolution and a quadratic measure, quantifyingO's information aboutS. Finally, it is shown that the four rules admit two solutions for the simplest case of a single elementary system: the Bloch ball and disc as state spaces for a qubit and rebit, respectively, together with their symmetries as time evolution groups. The reconstruction for arbitrarily many qubits is completed in a companion paper [P. A. Höhn and C. S. P. Wever, Phys. Rev. A 95 (2017) 012102] where an additional rule eliminates the rebit case. This approach is inspired by (but does not rely on) the relational interpretation and yields a novel formulation of quantum theory in terms of questions.

Futures within: Reversible time and house-building in Maputo, Mozambique

In this article, I introduce an anthropological approach to time and temporality which suggests that anticipatory actions are not always guided by futures separated from the present through a linear chronology. Whereas time is conventionally understood as a chronological series of succeeding moments, I argue that different temporalities might converge to create durations which cannot be gauged using a linear scale. I consequently explore anticipatory action as it pertains to durational time. As I will show, when temporal succession is discontinuous, linearity may be turned around so that (assumed) effects are revealed to be causes. Rather than functioning as the dominant temporal trope, linear sequentiality thus emerges as an effect of reversible time. I build my argument from an ethnographical examination of house-building practices in peri-urban areas of Maputo, Mozambique. According to house-builders, they build houses which will never be completed. Still, by pre-figuring the end-point as a likely failure, anticipatory action is turned inwards through a series of internal reversals. House-building is guided by seemingly incompatible social principles and through a series of temporal reversals, these tensions are momentarily resolved.