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Steffen Ducheyne, Pieter Present
In this article, we discuss the development of the concept of a 'law' (of nature) in the work of the Dutch natural philosopher and experimenter Petrus van Musschenbroek (1692-1761). Since Van Musschenbroek is commonly described as one of the first 'Newtonians' on the Continent in the secondary literature, we focus more specifically on its relation to Newton's views on this issue. Although he was certainly indebted to Newton for his thinking on laws (of nature), Van Musschenbroek's views can be seen to diverge from Newton's on crucial points...
October 13, 2017: British Journal for the History of Science
Ana Paula Bispo Silva, Jamily Alves da Silva
Phenomena involving electromagnetism and conservation of energy during the nineteenth century did not fit the reigning Newtonian paradigm. Among scholars, there was the need to explain such facts considering "something more" that had not yet been expressed. Through this explanation, Naturphilosophie, the philosophical branch associated with the German romantic movement of the nineteenth century, seems to offer new ways of understanding the sciences. In this article, we present main aspects of the work of Schelling, the main exponent of Naturphilosophie, and how his assumptions were inserted into the physical sciences to explain electromagnetism and conservation of energy...
July 2017: História, Ciências, Saúde—Manguinhos
Daniel Rauber, Peng Zhang, Volker Huch, Tobias Kraus, Rolf Hempelmann
Ionic liquids (ILs) exhibit tunable behaviour and properties that are due to their supramolecular structure. We synthesized a series of alkylated and fluorinated phosphonium dicyanamide ILs to study the relation between molecular structure and assembly with a focus on the roles of cation chain length and fluorination. Small angle X-ray scattering indicated a lamellar structure with long-range order for all fluorinated ILs, while alkylated ILs showed only the general structures of ILs, i.e., alternating a polar ionic-zone and a nonpolar alkyl-zone...
October 9, 2017: Physical Chemistry Chemical Physics: PCCP
Justin K S Tan, Sung-Yong Park, Hwa Liang Leo, Sangho Kim
White blood cells (WBCs) are the only cellular constituent containing genetic materials, and, hence, are candidate biomarkers for a host of diseases. However, conventional methods for WBC separation tend to have low sample purity and separation efficiency, which will have adverse implications on downstream polymerase chain reaction (PCR) analyses. In this study, we introduce a two-stage microfluidic device which harnesses the elastic property of a non-Newtonian fluid for size-based separation of WBCs from whole blood...
October 5, 2017: IEEE Transactions on Biomedical Circuits and Systems
Chuanbin Li, Boyang Qin, Arvind Gopinath, Paulo E Arratia, Becca Thomases, Robert D Guy
Many important biological functions depend on microorganisms' ability to move in viscoelastic fluids such as mucus and wet soil. The effects of fluid elasticity on motility remain poorly understood, partly because the swimmer strokes depend on the properties of the fluid medium, which obfuscates the mechanisms responsible for observed behavioural changes. In this study, we use experimental data on the gaits of Chlamydomonas reinhardtii swimming in Newtonian and viscoelastic fluids as inputs to numerical simulations that decouple the swimmer gait and fluid type in order to isolate the effect of fluid elasticity on swimming...
October 2017: Journal of the Royal Society, Interface
Anna Marie Roos
Martin Folkes (1690-1754) was Newton's protégé, an English antiquary, mathematician, numismatist and astronomer who would in the latter part of his career become simultaneously president of the Royal Society and of the Society of Antiquaries. Folkes took a Grand Tour from March 1733 to September 1735, recording the Italian leg of his journey from Padua to Rome in his journal. This paper examines Folkes's travel diary to analyse his Freemasonry, his intellectual development as a Newtonian and his scientific peregrination...
October 5, 2017: British Journal for the History of Science
Vikas Thondapu, Erhan Tenekecioglu, Eric K W Poon, Yoshinobu Onuma, Patrick W Serruys
No abstract text is available yet for this article.
July 18, 2017: European Heart Journal Cardiovascular Imaging
V V Rusakov, Yu L Raikher
The theory of orientational motion of a Brownian magnetic nanoparticle embedded in a viscoelastic medium and subjected to a time-dependent uniform magnetic field is developed. The rheology of the viscoelastic environment of the particle is modeled by the Jeffreys scheme, which under variation of a minimal number of parameters is able to resemble a wide range of soft materials: from a weakly structured (nearly Newtonian) polymer solution to a gel. It is shown that in the Jeffreys model, the diffusional orientational motion of a particle is a combination of two modes, which could be associated with a fast motion within the polymer mesh cell and a slow displacement that involves deformation of the mesh, respectively...
September 28, 2017: Journal of Chemical Physics
Jonathan F Kominsky, Brent Strickland, Annie E Wertz, Claudia Elsner, Karen Wynn, Frank C Keil
When object A moves adjacent to a stationary object, B, and in that instant A stops moving and B starts moving, people irresistibly see this as an event in which A causes B to move. Real-world causal collisions are subject to Newtonian constraints on the relative speed of B following the collision, but here we show that perceptual constraints on the relative speed of B (which align imprecisely with Newtonian principles) define two categories of causal events in perception. Using performance-based tasks, we show that triggering events, in which B moves noticeably faster than A, are treated as being categorically different from launching events, in which B does not move noticeably faster than A, and that these categories are unique to causal events (Experiments 1 and 2)...
September 1, 2017: Psychological Science
Aftab Ahmed, J I Siddique, Asif Mahmood
We investigate the behavior of a spherical cavity in a soft biological tissue modeled as a deformable porous material during an injection of non-Newtonian fluid that follows a power law model. Fluid flows into the neighboring tissue due to high cavity pressure where it is absorbed by capillaries and lymphatics at a rate proportional to the local pressure. Power law fluid pressure and displacement of a solid in the tissue are computed as function of radial distance and time. Numerical solutions indicate that shear thickening fluids exhibit less fluid pressure and induce small solid deformation as compared to shear thinning fluids...
September 28, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Pablo Montero de Hijes, Pablo Rosales-Pelaez, Chantal Valeriani, Peter N Pusey, Eduardo Sanz
In a recent molecular dynamics simulation work it has been shown that glasses composed of hard spheres crystallize via cooperative, stochastic particle displacements called avalanches [E. Sanz et al., Proc. Natl. Acad. Sci. USA 111, 75 (2014)PNASA60027-842410.1073/pnas.1308338110]. In this Rapid Communication we investigate if such a devitrification mechanism is also present when the dynamics is Brownian rather than Newtonian. The research is motivated in part by the fact that colloidal suspensions, an experimental realization of hard-sphere systems, undergo Brownian motion...
August 2017: Physical Review. E
Raz Halifa Levi, Yacov Kantor
We use Newtonian and overdamped Langevin dynamics to study long flexible polymers dragged by an external force at a constant velocity v. The work W performed by that force depends on the initial state of the polymer and the details of the process. The Jarzynski equality can be used to relate the nonequilibrium work distribution P(W) obtained from repeated experiments to the equilibrium free energy difference ΔF between the initial and final states. We use the power law dependence of the geometrical and dynamical characteristics of the polymer on the number of monomers N to suggest the existence of a critical velocity v_{c}(N), such that for v<v_{c} the reconstruction of ΔF is an easy task, while for v significantly exceeding v_{c} it becomes practically impossible...
August 2017: Physical Review. E
Andrea Colagrossi, Danilo Durante, Josep Bonet Avalos, Antonio Souto-Iglesias
Stokes' hypothesis, the zeroing of the bulk viscosity in a Newtonian fluid, is discussed in this paper. To this aim, a continuum macroscopic fluid domain is initially modeled as a Hamiltonian system of discrete particles, for which the interparticle dissipative forces are required to be radial in order to conserve the angular momentum. The resulting system of particles is then reconverted to the continuum domain via the framework of the smoothed particle hydrodynamics (SPH) model. Since an SPH-consistent approximation of the Newtonian viscous term in the momentum equation incorporates interparticle radial as well as nonradial terms, it is postulated that the latter must be null...
August 2017: Physical Review. E
Pierre Paga, Reimer Kühn
We study the large deviations of the magnetization at some finite time in the Curie-Weiss random field Ising model with parallel updating. While relaxation dynamics in an infinite-time horizon gives rise to unique dynamical trajectories [specified by initial conditions and governed by first-order dynamics of the form m_{t+1}=f(m_{t})], we observe that the introduction of a finite-time horizon and the specification of terminal conditions can generate a host of metastable solutions obeying second-order dynamics...
August 2017: Physical Review. E
S De, P Krishnan, J van der Schaaf, J A M Kuipers, E A J F Peters, J T Padding
HYPOTHESIS: Multiphase flow through porous media is important in a number of industrial, natural and biological processes. One application is enhanced oil recovery (EOR), where a resident oil phase is displaced by a Newtonian or polymeric fluid. In EOR, the two-phase immiscible displacement through heterogonous porous media is usually governed by competing viscous and capillary forces, expressed through a Capillary number Ca, and viscosity ratio of the displacing and displaced fluid. However, when viscoelastic displacement fluids are used, elastic forces in the displacement fluid also become significant...
September 20, 2017: Journal of Colloid and Interface Science
Tatiana A Ivanova, Olaf Lechtenfeld, Alexander D Popov
We consider pure SU(2) Yang-Mills theory on four-dimensional de Sitter space dS_{4} and construct a smooth and spatially homogeneous magnetic solution to the Yang-Mills equations. Slicing dS_{4} as R×S^{3}, via an SU(2)-equivariant ansatz, we reduce the Yang-Mills equations to ordinary matrix differential equations and further to Newtonian dynamics in a double-well potential. Its local maximum yields a Yang-Mills solution whose color-magnetic field at time τ∈R is given by B[over ˜]_{a}=-1/2I_{a}/(R^{2}cosh^{2}τ), where I_{a} for a=1, 2, 3 are the SU(2) generators and R is the de Sitter radius...
August 11, 2017: Physical Review Letters
Iman Dankar, Amira Haddarah, Fawaz El Omar, Francesc Sepulcre, Montserrat Pujolà
The effects of agar, alginate, lecithin and glycerol on the rheological properties of commercial potato puree were investigated and interpreted in terms of starch microstructural changes, and the applicability of the Cox-Merz rule was evaluated. Each additive was applied separately at two concentrations (0.5 and 1%). Microscopic observations revealed more swollen starch aggregations in lecithin and glycerol compared with those of potato puree and agar, consequently affecting the rheological properties of potato puree...
February 1, 2018: Food Chemistry
Andrea Montanino, Maurizio Angelillo, Anna Pandolfi
The air puff test is an in-vivo investigative procedure commonly utilized in ophthalmology to estimate the intraocular pressure. Potentially the test, quick and painless, could be combined with inverse analysis methods to characterize the patient-specific mechanical properties of the human cornea. A rapid localized air jet applied on the anterior surface induces the inward motion of the cornea, that interacts with aqueous humor-the fluid filling the narrow space between cornea and iris-with a strong influence on the dynamics of the cornea...
September 14, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Erik Alpizar-Reyes, Angélica Román-Guerrero, Raquel Gallardo-Rivera, Victor Varela-Guerrero, Julian Cruz-Olivares, César Pérez-Alonso
Tamarind seed mucilage (TSM) was extracted and obtained by spray drying. The power law model well described the rheological behavior of the TSM dispersions with determination coefficients R(2) higher than 0.99. According to power law model, non-Newtonian shear thinning behavior was observed at all concentrations (0.5%, 1%, 1.5% and 2%) and temperatures (25, 30, 40, and 60°C) studied. Increasing temperature decreased the viscosity and increased the flow behavior index, opposite effect was observed when increasing the concentration...
September 16, 2017: International Journal of Biological Macromolecules
Léo Garcia, Léa Jacquot, Elisabeth Charlaix, Benjamin Cross
Using a dynamic surface force apparatus, we investigate the nano-mechanics and the nano-rheology of an ionic liquid at dielectric and metallic solid surfaces. On smooth dielectric Pyrex surfaces, we find an ordered interfacial phase extending over less than 3 nm away from the top of the layer, with a compression modulus of 15 MPa extracted from the profile of the oscillatory forces. We discuss the boundary flow of the Newtonian bulk phase on this ordered interfacial layer. On metallic platinum surfaces, our hydrodynamic measurements evidence an interfacial soft solid layer extending up to 20 nm away from the top of the layer...
September 19, 2017: Faraday Discussions
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