Read by QxMD icon Read


S Sen, W Zhu, B G Aitken
The steady and oscillatory shear rate dependence of viscosity of a supercooled chalcogenide liquid of composition As10Se90 is measured at Newtonian viscosities ranging between 10(3) and 10(7) Pa s using capillary and parallel plate rheometry. The liquid displays strong violation of the Cox-Merz rule in the non-Newtonian regime where the viscosity under steady shear is nearly an order of magnitude lower than that under oscillatory shear. This behavior is argued to be related to the emergence of unusually large (6-8 nm) cooperatively rearranging regions with long relaxation times in the liquid that result from significant structural rearrangements under steady shear...
July 21, 2017: Journal of Chemical Physics
Philipp Kanehl, Holger Stark
We present a numerical study of dense colloidal suspensions in a pressure-driven microchannel flow in two dimensions. The colloids are modeled as elastic and frictional spheres suspended in a Newtonian fluid, which we simulate using the method of multiparticle collision dynamics. The model reproduces periodic velocity and density pulse trains, traveling upstream in the microchannel, which are found in experiments conducted by Isa et al. [Phys. Rev. Lett. 102, 058302 (2009)PRLTAO0031-900710.1103/PhysRevLett...
July 7, 2017: Physical Review Letters
Matthew C Miller, Philip W Fink, Paul William Macdermid, Blake G Perry, Stephen R Stannard
Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event...
July 21, 2017: Sports Biomechanics
C D'Onofrio, R van Loon, S Rolland, R Johnston, L North, S Brown, R Phillips, J Sienz
Cardiopulmonary bypass procedures are one of the most common operations and blood oxygenators are the centre piece for the heart-lung machines. Blood oxygenators have been tested as entire devices but intricate details on the flow field inside the oxygenators remain unknown. In this study, a novel method is presented to analyse the flow field inside oxygenators based on micro Computed Tomography (μCT) scans. Two Hollow Fibre Membrane (HFM) oxygenator prototypes were scanned and three-dimensional full scale models that capture the device-specific fibre distributions are set up for computational fluid dynamics analysis...
July 14, 2017: Medical Engineering & Physics
Emily E Riley, Eric Lauga
Many cells exploit the bending or rotation of flagellar filaments in order to self-propel in viscous fluids. While appropriate theoretical modeling is available to capture flagella locomotion in simple, Newtonian fluids, formidable computations are required to address theoretically their locomotion in complex, nonlinear fluids, e.g., mucus. Based on experimental measurements for the motion of rigid rods in non-Newtonian fluids and on the classical Carreau fluid model, we propose empirical extensions of the classical Newtonian resistive-force theory to model the waving of slender filaments in non-Newtonian fluids...
June 2017: Physical Review. E
Mathieu Bottier, Sylvain Blanchon, Gabriel Pelle, Emilie Bequignon, Daniel Isabey, André Coste, Estelle Escudier, James B Grotberg, Jean-François Papon, Marcel Filoche, Bruno Louis
Mucociliary clearance is one of the major lines of defense of the respiratory system. The mucus layer coating the pulmonary airways is moved along and out of the lung by the activity of motile cilia, thus expelling the particles trapped in it. Here we compare ex vivo measurements of a Newtonian flow induced by cilia beating (using micro-beads as tracers) and a mathematical model of this fluid flow, presented in greater detail in a second companion article. Samples of nasal epithelial cells placed in water are recorded by high-speed video-microscopy and ciliary beat pattern is inferred...
July 2017: PLoS Computational Biology
Anna Story, Zdzisław Jaworski
Results of numerical simulations of momentum transfer for a highly shear-thinning fluid (0.2% Carbopol) in a stirred tank equipped with a Prochem Maxflo T type impeller are presented. The simulation results were validated using LDA data and both tangential and axial force measurements in the laminar and early transitional flow range. A good agreement between the predicted and experimental results of the local fluid velocity components was found. From the predicted and experimental values of both tangential and axial forces, the power number, Po, and thrust number, Th, were also calculated...
2017: Chemické Zvesti
Christopher G McKnight, Joseph A Jude, Zhenqi Zhu, Reynold A Panettieri, Fred D Finkelman
IgE contributes to disease exacerbations but not to baseline airway hyperresponsiveness (AHR) in human asthma. In rodent allergic airway disease (AAD), mast cell and IgE dependence for the induction of AHR has only been observed when mice are immunized with a relatively weak allergen without adjuvant. To evaluate the role of IgE in murine AAD that is induced by a potent allergen, we inoculated BALB/c and FVB/N background wild-type, and IgE- or FcεRIα-deficient mice intratracheally with large or limiting doses of house dust mite extract (HDM) and evaluated AHR, pulmonary eosinophilia, goblet cell metaplasia, serum IgE, and lung mastocytosis...
July 12, 2017: American Journal of Respiratory Cell and Molecular Biology
M Farooq Wahab, Darshan C Patel, Rasangi M Wimalasinghe, Daniel W Armstrong
New stationary phases are continuously developed for achieving higher efficiencies and unique selectivities. The performance of any new phase can only be assessed when the columns are effectively packed under high pressure to achieve a stable bed. The science of packing columns with stationary phases is one of the most crucial steps to achieve consistent and reproducible high-resolution separations. A poorly packed column can produce non-Gaussian peak shapes and lower detection sensitivities. Given the ever larger number of stationary phases, it is impossible to arrive at a single successful approach...
July 12, 2017: Analytical Chemistry
Vikram Jadhao, Mark O Robbins
For decades, scientists have debated whether supercooled liquids stop flowing below a glass transition temperature [Formula: see text] or whether motion continues to slow gradually down to zero temperature. Answering this question is challenging because human time scales set a limit on the largest measurable viscosity, and available data are equally well fit to models with opposite conclusions. Here, we use short simulations to determine the nonequilibrium shear response of a typical glass-former, squalane...
July 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
Paul F Salipante, Charles A E Little, Steven D Hudson
Non-Newtonian fluids are susceptible to flow instabilities such as shear banding, in which the fluid may exhibit a markedly discontinuous viscosity at a critical stress. Here we report the characteristics and causes of a jetting flow instability of shear banding wormlike micelle solutions in microfluidic channels with rectangular cross sections over an intermediate volumetric flow regime. Particle-tracking methods are used to measure the three-dimensional flow field in channels of differing aspect ratios, sizes, and wall materials...
March 2017: Physical Review Fluids
Imene Chentir, Marwa Hamdi, Amel Doumandji, Abdelkadder Hadj Sadok, Hatem Ben Ouada, Moncef Nasri, Mourad Jridi
The interactive effects of light intensity and NaCl concentration were investigated for Spirulina two-step cultivation process using Full Factorial Design. In the experiment interval, light intensity had no effect while the NaCl concentration had significant effect on extracellular polymeric substances enhancement. Interestingly, results revealed a significant negative interaction between light and NaCl indicating that high NaCl concentration (40g.L(-1)) and low light intensity (10μmol photons m(-2)s(-1)) enhanced the EPS production...
July 5, 2017: International Journal of Biological Macromolecules
Noreen Sher Akbar, Adil Wahid Butt, Dharmendra Tripathi
BACKGROUND AND OBJECTIVES: This paper aims to investigate the unsteady flow of two types of nanofluids i.e Copper water nanofluids and Silver water nanofluids) through finite length non-uniform channel driven by peristaltic sinusoidal wave propagations. METHODS: The governing equations are reduced in linear form using dimensional analysis and considering the low Reynolds number and large wavelength approximations. The time dependent temperature field, axial velocity, transverse velocity and pressure difference are obtained analytically in closed form solution...
July 2017: Computer Methods and Programs in Biomedicine
Mario R Romano, Francesca Cuomo, Nicola Massarotti, Alessandro Mauro, Mohamed Salahudeen, Ciro Costagliola, Luigi Ambrosone
Rheological behavior of silicone oils,(CH3)3SiO-[Si(CH3)2O]n-Si(CH3)3, and their mixtures is studied. Shear stress measurements, in the temperature range 293-313 K, reveal that this family of polymers are shear thinning liquids with a yield stress below which no flow occurs. Experimental diagrams, i.e. shear stress versus shear rate, are satisfactorily described by the fluid model of Casson over a wide range of shear rates. In order to monitor the effect of temperature on fluid properties, Casson's rheological model is reformulated using the fictitious shear rate, γ ̇f, and the infinite- shear viscosity, η∞, as constitutive parameters...
July 7, 2017: Journal of Physical Chemistry. B
Niccolò Guicciardini
During the eighteenth century, several towns located in what is known today as the Suisse romande were extremely receptive toward scientific culture, and most notably Newtonianism. In this paper I deal with a nine-volume publication of Newton's Opera Omnia that was planned in Geneva and Lausanne during the late 1730s and 1740s. This publication has not received the attention it deserves. To the best of my knowledge, even an awareness of its existence is lacking in the literature devoted to the reception of Newtonianism...
July 1, 2017: History of Science; An Annual Review of Literature, Research and Teaching
Ruien Hu, John Crawshaw
A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer...
June 6, 2017: Journal of Visualized Experiments: JoVE
Ayham Zaitouny, Thomas Stemler, Michael Small
Miniature GPS devices now allow for measurement of the movement of animals in real time and provide high- quality and high-resolution data. While these new data sets are a great improvement, one still encounters some measurement errors as well as device failures. Moreover, these devices only measure position and require further reconstruction techniques to extract the full dynamical state space with the velocity and acceleration. Direct differentiation of position is generally not adequate. We report on the successful implementation of a shadowing filter algorithm that (1) minimizes measurement errors and (2) reconstructs at the same time the full phase-space from a position recording of a flying pigeon...
June 2017: Ecology and Evolution
Xiao Guo, Xiaofei Shang, Xuzheng Zhou, Baotang Zhao, Jiyu Zhang
In this study, we aimed to optimize the extraction of polysaccharides from the leaves of Rhododendron aganniphum and investigate its rheological properties and antioxidant activity. After optimizing the operating parameters using a Box-Behnken design (BBD), the results showed that the optimal ultrasound-assisted extraction conditions were as follows: extraction temperature, 55°C; liquid-solid ratio, 25:1; extraction time, 2.2h; and ultrasound treatment power, 200W. The optimized experimental yield of polysaccharides by ultrasound-assisted extraction (PUAE) was 9...
September 2017: Ultrasonics Sonochemistry
Daniel Vågberg, Peter Olsson, S Teitel
We report on numerical simulations of simple models of athermal, bidisperse, soft-core, massive disks in two dimensions, as a function of packing fraction ϕ, inelasticity of collisions as measured by a parameter Q, and applied uniform shear strain rate γ[over ̇]. Our particles have contact interactions consisting of normally directed elastic repulsion and viscous dissipation, as well as tangentially directed viscous dissipation, but no interparticle Coulombic friction. Mapping the phase diagram in the (ϕ,Q) plane for small γ[over ̇], we find a sharp first-order rheological phase transition from a region with Bagnoldian rheology to a region with Newtonian rheology, and show that the system is always Newtonian at jamming...
May 2017: Physical Review. E
Pertti Hari, Tuomas Aakala, Juho Aalto, Jaana Bäck, Jaakko Hollmén, Kalev Jõgiste, Kourosh Kabiri Koupaei, Mika A Kähkönen, Mikko Korpela, Liisa Kulmala, Eero Nikinmaa, Jukka Pumpanen, Mirja Salkinoja-Salonen, Pauliina Schiestl-Aalto, Asko Simojoki, Mikko Havimo
Isaac Newton's approach to developing theories in his book Principia Mathematica proceeds in four steps. First, he defines various concepts, second, he formulates axioms utilising the concepts, third, he mathematically analyses the behaviour of the system defined by the concepts and axioms obtaining predictions and fourth, he tests the predictions with measurements. In this study, we formulated our theory of boreal forest ecosystems, called NewtonForest, following the four steps introduced by Newton. The forest ecosystem is a complicated entity and hence we needed altogether 27 concepts to describe the material and energy flows in the metabolism of trees, ground vegetation and microbes in the soil, and to describe the regularities in tree structure...
2017: PloS One
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"