scholarly journals Voltage dependent models of the formative time delay in argon

2017 ◽  
Vol 15 (2) ◽  
pp. 81-93
Author(s):  
Suzana Stamenkovic ◽  
Vidosav Markovic ◽  
Aleksandar Jovanovic ◽  
Marjan Stankov
Keyword(s):  
Experimental Data ◽  
Data Analysis ◽  
Time Delay ◽  
Breakdown Voltage ◽  
Empirical Models ◽  
Formative Time ◽  
Voltage Dependent ◽  
Semi Empirical ◽  
Empirical Corrections ◽  
Good Agreement

Measurements of the formative time delay tf at different working voltages U in argon at low pressure are presented. The well-known decreasing voltage behavior of the formative time delay is theoretically described by different empirical and semi-empirical models. In addition to the introduced empirical models, some models from the literature are applied to elucidate experimentally obtained tf (U) dependence. However, the models from the literature show a good agreement with the experimental data only at low overvoltages ?U(?U=U-Us where Us is the static breakdown voltage). Therefore, empirical corrections are made based on data analysis, and good compatibility is achieved in a whole range of working voltages.

Fluid Forces Induced by Vortex Shedding

1976 ◽  
Vol 98 (1) ◽  
pp. 19-24 ◽  
Author(s):  
R. D. Blevins ◽  
T. E. Burton
Keyword(s):  
Experimental Data ◽  
Vortex Shedding ◽  
Model Parameters ◽  
Amplitude Dependence ◽  
Fluid Forces ◽  
At Resonance ◽  
Elastic Cylinders ◽  
Random Vibration Theory ◽  
Semi Empirical ◽  
Good Agreement

A semi-empirical, dynamic model for investigating the fluid forces induced on a bluff cylinder by vortex shedding is developed using random vibration theory. The model includes both spanwise correlation effects and the amplitude dependence of the correlated vortex forces. Model parameters are determined by experimental data. The results are then applied to determine the forces exerted on elastic cylinders at resonance with vortex shedding. The predictions are in good agreement with experimental data.

Measurement and Correlation of Solubility of Fructose Diphosphate Sodium in Ethanol + Water Mixtures

2014 ◽  
Vol 614 ◽  
pp. 65-69
Author(s):  
Yan Fei Wang ◽  
Yu Xiang Zhu ◽  
Xiao Yu Zhao ◽  
Shi Jie Xu ◽  
Lin Shan Hu ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Empirical Models ◽  
Binary Solvent ◽  
Experimental Solubility Data ◽  
Laser Monitoring ◽  
Experimental Solubility ◽  
Experimental Values ◽  
Semi Empirical ◽  
Laser Monitoring Observation Technique ◽  
Good Agreement

Using a laser monitoring observation technique, the solubility of fructose diphosphate sodium in binary solvent of ethanol + water mixtures was experimentally measured in the temperature ranging from 298.15 K to 333.15 K at atmospheric pressure. The solubility of fructose diphosphate sodium increased with an increase of temperature and quality percentage of water. Experimental solubility data were correlated with semi-empirical models; and the calculated solubilities of fructose diphosphate sodium show good agreement with the experimental values.

Current Affairs: Model Tests, Semi-Empirical Predictions and CFD Computations for Current Coefficients of Semi-Submersibles

2009 ◽  
Author(s):  
Guilherme Vaz ◽  
Olaf J. Waals ◽  
Harald Ottens ◽  
Fahd Fathi ◽  
Tim Le Soue¨f ◽  
...  
Keyword(s):  
Experimental Data ◽  
Empirical Models ◽  
Model Tests ◽  
Numerical Errors ◽  
Current Affairs ◽  
Rounded Corner ◽  
Model Predictions ◽  
Modeling Accuracy ◽  
Key Issues ◽  
Semi Empirical

Current loads on stationary vessels have been investigated as part of the Current Affairs Joint Industry Project (JIP). Model-tests, semi-empirical models and CFD methods were used to predict these loads. This paper examines one configuration out of the eight tested in the JIP; an idealized semi-submersible consisting of two square rounded-corner columns connected with a pontoon. The model experiments, empirical model predictions and CFD results are presented and discussed. ‘Blind’ and ‘Improved’ CFD computations (with and without knowledge of the experimental results) have been carried out by the JIP participants. Comparisons between these results are made, deviations from the experimental data are quantified and conclusions are drawn. Two key issues for modeling accuracy are identified and discussed; the location of the transition to turbulent flow and the control of the numerical errors.

Improving the Precision of Moisture Content Detection by Use of Electrical Resistance Method

2011 ◽  
Vol 239-242 ◽  
pp. 1339-1342
Author(s):  
Qiao Fang Zhou ◽  
Ying Chun Cai ◽  
Miao Xiang Huang
Keyword(s):  
Experimental Data ◽  
Moisture Content ◽  
Electrical Resistance ◽  
Empirical Models ◽  
Quercus Mongolica ◽  
The Real ◽  
Resistance Method ◽  
Weight Method ◽  
Measured Moisture Content ◽  
Good Agreement

Moisture content of Quercus mongolica Fisch was detected by use of electrical resistance method under 30~80°C, and the real moisture content of it was obtained with weight method. Based on experimental data two empirical models were established among real moisture content, temperature and measured moisture content which were detected by moisture content apparatus with temperature compensated and without temperature compensated, respectively. Results indicated that measured moisture content of Quercus mongolica Fisch had a good agreement with the real moisture content after the measured moisture content was corrected by any of the above two empirical models under 30~80°C and 7~29% moisture content.

Evaluation of Existing Semi-Empirical Models of Scour at a Submarine System

2018 ◽  
Author(s):  
Valeria S. Rego ◽  
Claudia M. P. M. Santos
Keyword(s):  
Experimental Data ◽  
Empirical Models ◽  
Small Scale ◽  
Scour Depth ◽  
Simplified Models ◽  
Practical Applications ◽  
Survey Statistics ◽  
Evaluation Of Data ◽  
Semi Empirical ◽  
Noncohesive Sediments

Assessment of scour below pipelines and gravity based structures in a submarine system is revisited with evaluation of data from two inspections and results for semi-empirical simplified models. Usually semi-empirical models are based on small scale experimental data that normally consider uniform and noncohesive sediments and have been questioned as to their practical applications. Recent local metocean data is used to revisit predictions of onset of scour and scour depth for the system, which are compared to survey statistics.

Empirical and semiempirical models of the formative time delay in nitrogen

2008 ◽  
Vol 86 (7) ◽  
pp. 947-951
Author(s):  
V Lj Marković ◽  
S N Stamenković ◽  
S R Gocić
Keyword(s):  
Time Delay ◽  
Time Dependence ◽  
Voltage Drop ◽  
Electrical Breakdown ◽  
Breakdown Time ◽  
Formative Time ◽  
Delay Times ◽  
Statistical Time ◽  
Semiempirical Models ◽  
Good Agreement

The formative time dependence on working voltages tf(U) in nitrogen is determined: (1) from the Laue diagrams, by taking the values where the linear approximation of the electrical breakdown time delay (td) intersects the time axis, (2) from histograms, by taking the minimum values of the delay times for the formative time, and (3) from a difference tf = [Formula: see text] – [Formula: see text] ≈ [Formula: see text] – σ (td), where standard deviation σ,(td) is approximately equal to the mean of the statistical time delay [Formula: see text]. The breakdown time delay measurements are supported by oscilloscopic measurements of the voltage drop and the current rise time during inception of the discharge. Several simple models were applied to describe the experimental formative time dependence on working voltages tf,(U) and a good agreement with experimental data was found.PACS Nos.: 51.50.+v, 52.80.–s

Temperature dependence of dielectric properties of moist soils

2008 ◽  
Vol 45 (6) ◽  
pp. 888-894 ◽  
Author(s):  
Arun P. Jaganathan ◽  
Erez N. Allouche
Keyword(s):  
Experimental Data ◽  
Dielectric Properties ◽  
Land Mines ◽  
Temperature Dependency ◽  
Moisture Contents ◽  
Moist Sand ◽  
Proposed Model ◽  
Dielectric Model ◽  
Semi Empirical ◽  
Good Agreement

Heating of soil using microwaves has several applications in geosciences, including soil remediation, neutralization of land mines, and microwave-enhanced thermography. Numerical simulation of microwave-induced soil heating processes requires knowledge of the electrical properties of the soil as a function of temperature, moisture content, and frequency of the electromagnetic wave. This paper describes a semi-empirical model for calculating the dielectric properties of moist soils at various moisture contents, temperatures, and frequencies (within the band of 1–10 GHz). The proposed model is an extension of the generalized refractive mixing dielectric model (GRMDM) for moist soils. Predictions of the proposed model were found to be in good agreement with experimental data reported in the literature. Results of a parametric study suggest that the temperature dependency of the dielectric properties of moist sand is more pronounced for higher volumetric moisture contents.

scholarly journals Similarity Analysis of Projectile Penetration into Concrete

2018 ◽  
Vol 68 (4) ◽  
pp. 417
Author(s):  
Meng Huang ◽  
Zhuo-Cheng Ou ◽  
Yi Tong ◽  
Zhuo-Ping Duan ◽  
Feng-Lei Huang
Keyword(s):  
Experimental Data ◽  
Impact Velocity ◽  
Similarity Theory ◽  
Full Scale ◽  
Similarity Analysis ◽  
Font Size ◽  
Depth Of Penetration ◽  
Incomplete Similarity ◽  
Semi Empirical ◽  
Good Agreement

<p><span style="font-size: 10px;">This paper presents a dimensionless model for the depth of penetration (DOP) of a projectile penetrating into a concrete target, based on the similarity theory involving intermediate asymptotics, complete similarity, and incomplete similarity. The calculated numerical results are in good agreement with previous experimental data, including two sets of full-scale and twenty-four sets of sub-scale penetration of non-deformable projectiles into concrete targets. Moreover, compared with several empirical and semi-empirical DOP models, the new model is applicable within a relatively broader range, including the penetration of both sub-scale and full-scale projectiles. For the limitations of the validity, dimensionless parameters </span><em style="font-size: 10px;">Π</em><sub>3  </sub><span style="font-size: 10px;">= </span><em style="font-size: 10px;">ϕ<sub>t</sub></em><span style="font-size: 10px;">/</span><em style="font-size: 10px;">ϕ </em><span style="font-size: 10px;">larger than 12, </span><em style="font-size: 10px;">Π</em><sub>4 </sub><span style="font-size: 10px;">= (</span><em style="font-size: 10px;">ϕ</em><sup>3</sup><em style="font-size: 10px;">f<sub>c</sub></em><span style="font-size: 10px;">)/(</span><em style="font-size: 10px;">Mv</em><sub>0</sub><sup>2</sup><span style="font-size: 10px;">) smaller than 0.1, and the initial impact velocity of the projectile less than about 900 to 1000m/s are necessary for the model.</span></p>

α-Decay half-lives of even–even nuclei of Pb, Po, Rn and Ra isotopes

2019 ◽  
Vol 28 (03) ◽  
pp. 1950017 ◽  
Author(s):  
S. S. Hosseini ◽  
H. Hassanabadi ◽  
Dashty T. Akrawy
Keyword(s):  
Experimental Data ◽  
Potential Barrier ◽  
Ground State ◽  
Α Decay ◽  
Model Based ◽  
Semi Empirical ◽  
Good Agreement

In the present work, we intended to study the [Formula: see text]-decay half-lives of the even–even nuclei from [Formula: see text]Po to [Formula: see text]Ra in ground state. We investigated a semi-empirical, one-parameter model based on tunneling through a potential barrier with the centrifugal and overlapping effects. Half-lives of [Formula: see text]-decay of even–even nuclei calculated by using different versions of proximity potentials (gpp77, MCW76 and MB77) are compared to experimental data. Also, the computed half-lives are compared with the Royer formula, Akrawy and Poenaru (AKRE) formula, modify Ren (MRen B) formula and Denisov–Khudenko (DEKH) formula and with the experimental data. The results are in good agreement with the experimental data.

Theoretical approaches on the α-decay of spherical Bismuth isotopes

2018 ◽  
Vol 27 (03) ◽  
pp. 1850022 ◽  
Author(s):  
S. S. Hosseini ◽  
H. Hassanabadi
Keyword(s):  
Experimental Data ◽  
Potential Model ◽  
Alpha Decay ◽  
Empirical Models ◽  
Empirical Formulas ◽  
Proximity Potential ◽  
Α Decay ◽  
Empirical Estimates ◽  
Theoretical Approaches ◽  
Good Agreement

In this paper, the alpha decay process is investigated through the theoretical approaches for spherical Bismuth (Bi) isotopes in the range 187 [Formula: see text] A [Formula: see text] 214. The results are compared with the experimental data for isotopes of Bi with the modified Coulomb and proximity potential model (MCPPM). We analyze the systematics of alpha decay half-life (HL) of Bi isotopes versus the decay energy and the total [Formula: see text]-kinetic energy. The results and their systematics are compared with the available experimental data and with those data obtained from empirical models as the Viola-Seaborg (VS) formula, Royer (R) and the two versions of modified Brown (mB) empirical formulas. The computed half-lives (HLs) are compared with the experimental data and also with the existing empirical estimates and are found in good agreement.

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