scholarly journals Non-linear effects in the oscillating drop method for viscosity measurements

2020 ◽  
Vol 48 (3) ◽  
pp. 253-277 ◽  
Author(s):  
RAINER K. WUNDERLICH ◽  
MARKUS MOHR
Keyword(s):  
Time Constant ◽  
Space Station ◽  
Surface Oscillation ◽  
Temperature Dependent Viscosity ◽  
Temperature Range ◽  
Drop Method ◽  
Sample Shape ◽  
Decay Times ◽  
Non Linear ◽  
Oscillation Decay

The contribution of non-linear fluid flow effects to the damping of surface oscillations in the oscillation drop method was investigated in a series of experiments in an electromagnetic levitation device installed on the International Space station, ISS-EML. In order to correctly evaluate the damping time constant from measured surface oscillation decays the effect of a modulated signal response on measured surface oscillation decay curves was investigated. It could be shown that various experimentally observed signal patterns could be well represented by a modulated response. The physical origin of such modulations is seen in rotation and precession. Over a temperature range of 220 K covered by different surface oscillation excitation pulses with an initial sample shape deformation of 5 – 10% the amplitude of surface oscillations as a function of time could be very well represented by a Lamb type damping with a temperature dependent viscosity. A direct comparison of surface oscillation decay times measured in the same temperature range but for different oscillation amplitudes showed no non-linear contribution to the damping time constant with a confidence level better 10%.

Non-linear ultrasonic and viscoelastic properties of gelatine investigated in the temperature range of 30 °C–60 °C

2021 ◽  
Vol 33 (2) ◽  
pp. 022002
Author(s):  
Jan Dirk Heyns ◽  
Esam T. Ahmed Mohamed ◽  
Nico F. Declercq
Keyword(s):  
Viscoelastic Properties ◽  
Temperature Range ◽  
Non Linear

Properties of spontaneous inhibitory synaptic currents in cultured rat spinal cord and medullary neurons

1996 ◽  
Vol 76 (1) ◽  
pp. 448-460 ◽  
Author(s):  
C. A. Lewis ◽  
D. S. Faber
Keyword(s):  
Spinal Cord ◽  
Time Constant ◽  
Decay Time ◽  
Cultured Cells ◽  
Decay Time Constant ◽  
Inhibitory Synapses ◽  
Gamma Aminobutyric Acid ◽  
Postsynaptic Receptor ◽  
Decay Times ◽  
Medullary Neurons

1. To identify the type(s) and properties of inhibitory postsynaptic receptor(s) involved in synaptic transmission in cultured rat embryonic spinal cord and medullary neurons, we have used whole cell patch-clamp techniques to record miniature inhibitory postsynaptic currents (mIPSCs) in the presence of tetrodotoxin, DL-2-amino-5-phosphonovaleric acid, and 6-cyano-7-nitroquinoxaline-2,3-dione. 2. The mIPSCs recorded from both spinal cord and medullary neurons had skewed amplitude distributions. 3. The glycinergic antagonist strychnine and the GABAergic antagonist bicuculline each decreased both the frequency and mean peak amplitudes of mIPSCs. We conclude that both glycine and gamma-aminobutyric acid (GABA) are neurotransmitters at inhibitory synapses in our cultured cells. 4. Most (approximately 96-97%) mIPSCs decay with single-exponential time constants, and decay time distributions were consistently best fitted by the sum of four Gaussians with decay constants as follows: D1 = 5.8 +/- 0.1 (SE) ms (n = 63), D2 = 12.2 +/- 0.2 ms (n = 61), D3 = 23.2 +/- 0.4 ms (n = 54), and D4 = 44.7 +/- 1.0 ms (n = 57). We conclude that the four classes of decay times represent kinetically different inhibitory postsynaptic receptor populations. 5. Strychnine and bicuculline usually had one of two different effects on the mIPSC decay time constant distributions; either selective decreases in the frequency of mIPSCs with decay times in certain classes (i.e., the D1 class was reduced by bicuculline, the D2 class by strychnine, and the D3 and D4 classes by both antagonists) or a nonselective depression in the frequency of mIPSCs with decay times in all four classes. The particular effect observed in a given neuron was correlated with the presence or absence of ATP and guanosine 5'-triphosphate (GTP) in the patch pipette. Namely, in 71% of the antagonist applications where the pipette contained ATP and GTP, the result was a nonselective decrease in mIPSCs in all decay time constant classes. Conversely, in 54% of the antagonist applications in their absence, the result was a selective decrease in the frequency of mIPSCs in specific decay time constant classes. 6. In some experiments, mIPSCs reappeared in antagonist solution after an essentially complete block. Recovery from block in the continued presence of antagonist was never observed in the absence of ATP and GTP (8 neurons), and, at the same time, 5 of 9 neurons patched with ATP and GTP in the pipette did show recovery (56%).

scholarly journals Selecting Ultracapacitors for Smoothing Voltage Deviations in Local Grids Fed by Transformer with Tap-Changer and Distributed PV Facilities

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 357 ◽  
Author(s):  
Oz Sorkin ◽  
Eliyahu Farber ◽  
Moshe Averbukh
Keyword(s):  
Time Constant ◽  
Power Plants ◽  
Numerical Procedure ◽  
Voltage Regulation ◽  
Solar Irradiation ◽  
Approximation Procedure ◽  
Non Linear ◽  
Low Pass ◽  
Linear Circuits ◽  
Selection Of

Widespread use of photovoltaic (PV) small and middle-power plants close or inside existing townships and villages may cause significant deviations of the grid voltage. Owing to the oscillation of solar irradiation and corresponding power flows these voltage instabilities can damage equipment and must be prevented. Designated for the voltage regulation tap-changers in distribution transformers located in a significant distance of such settlements have a sluggish response time. As a possible answer for their delay is the smoothing energy of flows in PV power installation by intermittent capacitor low-pass filtering (LPF) located near those PV facilities. The application of ultracapacitors (UC) for LPF is remarkable due to their sustainability and relatively low costs of energy storage. The parameters selection of such appliances is a well-designed procedure for linear circuits. However, DC–AC inverters in PV facilities are represented by a power (instead of a voltage) source. As a result, the total circuit including such LPF becomes a non-linear and its transient process and consequently, its efficiency is difficult to assess requiring each time of development the UC storage an application complex numerical procedure. Engineers are usual to work with linear circuits that are describing fine by a time constant is designated as a multiplication of a capacitance times load equivalent resistance. In the case of PV DC–AC inverters, such an approach can be applied as well but a value of a time constant should be corrected. Considering a significant cost of UC storage, the non-optimal selection of a correcting coefficient may cause considerable loses. Submitted in the presented article is an original approximation procedure giving an efficiently approachable technique to select correcting coefficient for describing non-linear dynamic process by its linear analog. This way the development low-pass UC filtering in electrical systems with PV plants becomes more efficient and simpler task.

On a Type of Automatically Interrupted Triode Oscillations

1930 ◽  
Vol 26 (2) ◽  
pp. 236-251
Author(s):  
J. A. Ratcliffe ◽  
L. G. Vedy
Keyword(s):  
Time Constant ◽  
Linear Resistance ◽  
Non Linear

A type of automatically interrupted triode oscillations is described which depends on the interaction between an oscillating triode circuit and. a circuit containing a non-linear resistance and a time-constant device. The theory of the circuit is developed and tested experimentally by means of oscillograms. The theory of the rise and decay of currents in a circuit containing an inductance and a non-linear resistance is dealt with in an appendix.

scholarly journals The association between diurnal temperature range and childhood hand, foot, and mouth disease: a distributed lag non-linear analysis

2017 ◽  
Vol 145 (15) ◽  
pp. 3264-3273 ◽  
Author(s):  
FEI YIN ◽  
YUE MA ◽  
XING ZHAO ◽  
QIANG LV ◽  
YAQIONG LIU ◽  
...  
Keyword(s):  
Diurnal Temperature Range ◽  
Foot And Mouth Disease ◽  
Sichuan Province ◽  
Mouth Disease ◽  
Diurnal Temperature ◽  
Temperature Range ◽  
Distributed Lag ◽  
Risk Estimates ◽  
Non Linear ◽  
Foot And Mouth

SUMMARYIn recent years, hand, foot, and mouth disease (HFMD) has been increasingly recognized as a critical challenge to disease control and prevention in China. Previous studies have found that meteorological factors such as mean temperature and relative humidity were associated with HFMD. However, little is known about whether the diurnal temperature range (DTR) has any impact on HFMD. This study aimed to quantify the impact of DTR on childhood HFMD in 18 cities in Sichuan Province. A distributed lag non-linear model was adopted to explore the temporal lagged association of daily temperature with age-, gender- and pathogen-specific HFMD. A total of 290 123 HFMD cases aged 0–14 years were reported in the 18 cities in Sichuan Province. The DTR–HFMD relationships were non-linear in all subgroups. Children aged 6–14 years and male children were more vulnerable to the temperature changes. Large DTR had the higher risk estimates of HFMD incidence in cases of EV71 infection, while small DTR had the higher risk estimates of HFMD incidence in cases of CV-A16 infection. Our study suggested that DTR played an important role in the transmission of HFMD with non-linear and delayed effects.

Influence of Aggregation on the Fluorescence Decay of Organic Laser Dyes

1978 ◽  
Vol 33 (1) ◽  
pp. 98-104 ◽  
Author(s):  
J. Knof ◽  
F.-J. Theiss ◽  
J. Weber
Keyword(s):  
Decay Time ◽  
Fluorescence Decay ◽  
Laser Dyes ◽  
Temperature Range ◽  
Arrhenius Relationship ◽  
Decay Times ◽  
Organic Laser ◽  
Aggregated Molecules

Singlet decay times in dependence on temperature, concentration, solvent and detergent were measured in solutions of organic laser dyes. In the temperature range from 300 K to 115 K the reciprocal decay time obeys an Arrhenius relationship, the parameters of which were determined. Additional measurements were carried out on Acridinorange because a biexponential fluorescence decay due to monomers (τ = 4.2 ns) and aggregated molecules (τ = 14.7 ns) was found.

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