scholarly journals Determination of ζ-Potential and Tortuosity in Rat Organotypic Hippocampal Cultures from Electroosmotic Velocity Measurements under Feedback Control

2009 ◽  
Vol 81 (8) ◽  
pp. 3001-3007 ◽  
Author(s):  
Yifat Guy ◽  
Robert J. Muha ◽  
Mats Sandberg ◽  
Stephen G. Weber
Keyword(s):  
Feedback Control ◽  
Velocity Measurements ◽  
Ζ Potential ◽  
Hippocampal Cultures ◽  
Electroosmotic Velocity

scholarly journals Determination of ζ-Potential in Rat Organotypic Hippocampal Cultures

2008 ◽  
Vol 94 (11) ◽  
pp. 4561-4569 ◽  
Author(s):  
Yifat Guy ◽  
Mats Sandberg ◽  
Stephen G. Weber
Keyword(s):  
Ζ Potential ◽  
Hippocampal Cultures

scholarly journals Mass determination of the 1:3:5 near-resonant planets transiting GJ 9827 (K2-135)

2018 ◽  
Vol 618 ◽  
pp. A116 ◽  
Author(s):  
J. Prieto-Arranz ◽  
E. Palle ◽  
D. Gandolfi ◽  
O. Barragán ◽  
E. W. Guenther ◽  
...  
Keyword(s):  
Planetary System ◽  
Initial Conditions ◽  
Dynamical Evolution ◽  
Space Mission ◽  
Mass Determination ◽  
Velocity Measurements ◽  
Orbital Periods ◽  
The Masses ◽  
Better Than

Context. Multiplanet systems are excellent laboratories to test planet formation models as all planets are formed under the same initial conditions. In this context, systems transiting bright stars can play a key role, since planetary masses, radii, and bulk densities can be measured. Aims. GJ 9827 (K2-135) has recently been found to host a tightly packed system consisting of three transiting small planets whose orbital periods of 1.2, 3.6, and 6.2 days are near the 1:3:5 ratio. GJ 9827 hosts the nearest planetary system (~30 pc) detected by NASA’s Kepler or K2 space mission. Its brightness (V = 10.35 mag) makes the star an ideal target for detailed studies of the properties of its planets. Methods. Combining the K2 photometry with high-precision radial-velocity measurements gathered with the FIES, HARPS, and HARPS-N spectrographs we revised the system parameters and derive the masses of the three planets. Results. We find that GJ 9827 b has a mass of Mb = 3.69−0.46+0.48 M⊕ and a radius of Rb = 1.58−0.13+0.14 R⊕, yielding a mean density of ρb = 5.11−1.27+1.74 g cm−3. GJ 9827 c has a mass of Mc = 1.45−0.57+0.58 M⊕, radius of Rc = 1.24−0.11+0.11 R⊕, and a mean density of ρc = 4.13−1.77+2.31 g cm−3. For GJ 9827 d, we derive Md = 1.45−0.57+0.58 M⊕, Rd = 1.24−0.11+0.11 R⊕, and ρd = 1.51−0.53+0.71 g cm−3. Conclusions. GJ 9827 is one of the few known transiting planetary systems for which the masses of all planets have been determined with a precision better than 30%. This system is particularly interesting because all three planets are close to the limit between super-Earths and sub-Neptunes. The planetary bulk compositions are compatible with a scenario where all three planets formed with similar core and atmosphere compositions, and we speculate that while GJ 9827 b and GJ 9827 c lost their atmospheric envelopes, GJ 9827 d maintained its primordial atmosphere, owing to the much lower stellarirradiation. This makes GJ 9827 one of the very few systems where the dynamical evolution and the atmosphericescape can be studied in detail for all planets, helping us to understand how compact systems form and evolve.

Determination of global kinetic parameters by optimization procedure using burning velocity measurements

2018 ◽  
Vol 13 (6) ◽  
pp. 50
Author(s):  
Gleb V. Grenkin ◽  
Alexander Yu. Chebotarev ◽  
Valeri I. Babushok ◽  
Sergey S. Minaev
Keyword(s):  
Kinetic Parameters ◽  
Equivalence Ratio ◽  
Reaction Rate ◽  
Functional Dependence ◽  
Burning Velocity ◽  
Optimization Procedure ◽  
Optimal Parameters ◽  
Velocity Measurements ◽  
Equilibrium Calculations

The optimization procedure was developed to derive the global kinetic parameters using experimental dependence of burning velocity on the equivalence ratio. The simple model of laminar premixed flame propagation with assumed constant parameters was used to demonstrate the features of the suggested procedure. The suggested method allows finding optimal parameters for the defined functional dependence of the reaction rate on the temperature and reactant concentrations. The dependence of combustion adiabatic temperature on equivalence ratio is assumed to be known from the flame equilibrium calculations. The global kinetic parameters of combustion reaction were determined for methane, ethylene and propane mixtures with air on the basis of experimental data on burning velocity as function of the equivalence ratio. The calculated overall kinetic parameters are compared with parameters obtained by other methods within similar global model.

Acoustic Phase Velocity Measurements along General Directions in Non-Isotropic Crystals. I. Elastic Properties of Monoclinic K3Co(CN)6

1971 ◽  
Vol 49 (12) ◽  
pp. 1597-1605 ◽  
Author(s):  
T. H. Chou ◽  
S. L. McBride ◽  
N. Rumin
Keyword(s):  
Elastic Constants ◽  
Experimental Error ◽  
Acoustic Velocity ◽  
Acoustic Energy ◽  
Perturbation Calculation ◽  
Velocity Measurements ◽  
Phase Velocities ◽  
Low Symmetry ◽  
Acoustic Phase

The complete elastic constants tensor of monoclinic potassium cobalticyanide [K3Co(CN)6] has been determined from measured ultrasonic phase velocities. These were obtained as a function of direction in several crystal planes by measuring the acoustic energy reflection coefficient at a liquid–solid interface as a function of angle and plane of incidence. The measurements were made at 27.6 MHz in p-xylene at 21.5 °C. The elastic constants were determined using an existing perturbation method. Velocities calculated from the derived elastic constants are in agreement with the measured velocities to within experimental error and the approximations in the perturbation calculation. The usefulness of this method for the determination of the elastic constants of low symmetry crystals is thus established. The Debye temperature of K3Co(CN)6 is estimated from the results to be 290 ± 10 °K with a corresponding mean acoustic velocity of 2560 ± 80 m/s.

scholarly journals Creating Nodes at Selected Locations in a Harmonically Excited Structure Using Feedback Control and Green’s Function

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Bassam A. Albassam
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Green’S Function ◽  
Green's Function ◽  
Nodal Point ◽  
Control Force ◽  
Velocity Measurements ◽  
Numerical Examples ◽  
Control Forces

The paper deals with designing a control force to create nodal point(s) having zero displacements and/or zero slopes at selected locations in a harmonically excited vibrating structure. It is shown that the steady-state vibrations at desired points can be eliminated using feedback control forces. These control forces are constructed from displacement and/or velocity measurements using sensors located either at the control force position or at some other locations. Dynamic Green’s function is exploited to derive a simple and exact closed from expression for the control force. Under a certain condition, this control force can be generated using passive elements such as springs and dampers. Numerical examples demonstrate the applicability of the method in various cases.

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